diff --git a/DESCRIPTION b/DESCRIPTION
index 81f1871e..e77f331a 100755
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -4,7 +4,7 @@ Title: Tools for basic signal processing in epidemiology
 Version: 0.8.5
 Authors@R: c(
     person("Jacob", "Bien", role = "ctb"),
-    person("Logan", "Brooks", email = "lcbrooks@andrew.cmu.edu", role = c("aut", "cre")),
+    person("Logan", "Brooks", , "lcbrooks@andrew.cmu.edu", role = c("aut", "cre")),
     person("Rafael", "Catoia", role = "ctb"),
     person("Nat", "DeFries", role = "ctb"),
     person("Daniel", "McDonald", role = "aut"),
@@ -15,16 +15,22 @@ Authors@R: c(
     person("Evan", "Ray", role = "aut"),
     person("Dmitry", "Shemetov", role = "ctb"),
     person("Ryan", "Tibshirani", role = "aut"),
-    person("Lionel", "Henry", role = "ctb", comment = "Author of included rlang fragments"),
-    person("Hadley", "Wickham", role = "ctb", comment = "Author of included rlang fragments"),
-    person("Posit", role = "cph", comment = "Copyright holder of included rlang fragments")
+    person("Lionel", "Henry", role = "ctb",
+           comment = "Author of included rlang fragments"),
+    person("Hadley", "Wickham", role = "ctb",
+           comment = "Author of included rlang fragments"),
+    person("Posit", role = "cph",
+           comment = "Copyright holder of included rlang fragments")
   )
-Description: This package introduces a common data structure for epidemiological
-    data reported by location and time, provides another data structure to
-    work with revisions to these data sets over time, and offers associated
-    utilities to perform basic signal processing tasks.
+Description: This package introduces a common data structure for
+    epidemiological data reported by location and time, provides another
+    data structure to work with revisions to these data sets over time,
+    and offers associated utilities to perform basic signal processing
+    tasks.
 License: MIT + file LICENSE
-Copyright: file inst/COPYRIGHTS
+URL: https://cmu-delphi.github.io/epiprocess/
+Depends:
+    R (>= 3.6)
 Imports:
     checkmate,
     cli,
@@ -58,18 +64,16 @@ VignetteBuilder:
     knitr
 Remotes:
     cmu-delphi/epidatr,
-    reconverse/outbreaks,
-    glmgen/genlasso
+    glmgen/genlasso,
+    reconverse/outbreaks
 Config/testthat/edition: 3
 Config/testthat/parallel: true
+Copyright: file inst/COPYRIGHTS
 Encoding: UTF-8
 LazyData: true
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.3.2
-Depends:
-    R (>= 2.10)
-URL: https://cmu-delphi.github.io/epiprocess/
-Collate:
+Collate: 
     'archive.R'
     'autoplot.R'
     'correlation.R'
diff --git a/NEWS.md b/NEWS.md
index 5b231126..8bdb8c47 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -5,7 +5,8 @@ Pre-1.0.0 numbering scheme: 0.x will indicate releases, while 0.x.y will indicat
 # epiprocess 0.9
 
 ## Breaking changes
-- In `epi[x]_slide`:
+
+- In `epi[x]_slide`
   - `names_sep` is deprecated, and if you return data frames from your
     computations, they will no longer be unpacked into separate columns with
     name prefixes; instead:
@@ -15,12 +16,18 @@ Pre-1.0.0 numbering scheme: 0.x will indicate releases, while 0.x.y will indicat
       packed data.frame-class column (see `tidyr::pack`).
   - `as_list_col` is deprecated; you can now directly return a list from your
     slide computations instead.
+- `additional_metadata` is no longer accepted in `as_epi_df()` or
+  `as_epi_archive()`. Use the new `other_keys` arg to specify additional key
+  columns, such as age group columns or other demographic breakdowns.
+  Miscellaneous metadata are no longer handled by `epiprocess`, but you can use
+  R's built-in `attr<-` instead for a similar feature.
 
 ## Improvements
 
 - Added `complete.epi_df`, which fills in missing values in an `epi_df` with
   `NA`s. Uses `tidyr::complete` underneath and preserves `epi_df` metadata.
-- Inclusion of the function `revision_summary` to provide basic revision information for `epi_archive`s out of the box. (#492)
+- Inclusion of the function `revision_summary` to provide basic revision
+  information for `epi_archive`s out of the box. (#492)
 
 ## Bug fixes
 
@@ -87,8 +94,8 @@ Pre-1.0.0 numbering scheme: 0.x will indicate releases, while 0.x.y will indicat
   - Multiple "data-masking" tidy evaluation expressions can be passed in via
     `...`, rather than just one.
   - Additional tidy evaluation features from `dplyr::mutate` are supported: `!!
-    name_var := value`, unnamed expressions evaluating to data frames, and `=
-    NULL`; see `?epi_slide` for more details.
+name_var := value`, unnamed expressions evaluating to data frames, and `=
+NULL`; see `?epi_slide` for more details.
 
 ## Cleanup
 
diff --git a/R/archive.R b/R/archive.R
index eb66e364..fbcc3c36 100644
--- a/R/archive.R
+++ b/R/archive.R
@@ -179,7 +179,8 @@ NULL
 #'
 #' * `geo_type`: the type for the geo values.
 #' * `time_type`: the type for the time values.
-#' * `additional_metadata`: list of additional metadata for the data archive.
+#' * `other_keys`: any additional keys as a character vector.
+#'    Typical examples are "age" or sub-geographies.
 #'
 #' While this metadata is not protected, it is generally recommended to treat it
 #'  as read-only, and to use the `epi_archive` methods to interact with the data
@@ -209,10 +210,8 @@ NULL
 #' if the time type is not recognized.
 #' @param other_keys Character vector specifying the names of variables in `x`
 #'   that should be considered key variables (in the language of `data.table`)
-#'   apart from "geo_value", "time_value", and "version".
-#' @param additional_metadata List of additional metadata to attach to the
-#'   `epi_archive` object. The metadata will have the `geo_type` field; named
-#'   entries from the passed list or will be included as well.
+#'   apart from "geo_value", "time_value", and "version". Typical examples
+#'   are "age" or more granular geographies.
 #' @param compactify Optional; Boolean. `TRUE` will remove some
 #'   redundant rows, `FALSE` will not, and missing or `NULL` will remove
 #'   redundant rows, but issue a warning. See more information at `compactify`.
@@ -293,7 +292,6 @@ new_epi_archive <- function(
     geo_type,
     time_type,
     other_keys,
-    additional_metadata,
     compactify,
     clobberable_versions_start,
     versions_end,
@@ -350,7 +348,7 @@ new_epi_archive <- function(
       DT = compactified,
       geo_type = geo_type,
       time_type = time_type,
-      additional_metadata = additional_metadata,
+      other_keys = other_keys,
       clobberable_versions_start = clobberable_versions_start,
       versions_end = versions_end
     ),
@@ -423,7 +421,6 @@ is_locf <- function(vec, tolerance) { # nolint: object_usage_linter
 validate_epi_archive <- function(
     x,
     other_keys,
-    additional_metadata,
     compactify,
     clobberable_versions_start,
     versions_end) {
@@ -434,9 +431,6 @@ validate_epi_archive <- function(
   if (any(c("geo_value", "time_value", "version") %in% other_keys)) {
     cli_abort("`other_keys` cannot contain \"geo_value\", \"time_value\", or \"version\".")
   }
-  if (any(names(additional_metadata) %in% c("geo_type", "time_type"))) {
-    cli_warn("`additional_metadata` names overlap with existing metadata fields \"geo_type\" or \"time_type\".")
-  }
 
   # Conduct checks and apply defaults for `compactify`
   assert_logical(compactify, len = 1, any.missing = FALSE, null.ok = TRUE)
@@ -485,8 +479,7 @@ as_epi_archive <- function(
     x,
     geo_type = deprecated(),
     time_type = deprecated(),
-    other_keys = character(0L),
-    additional_metadata = list(),
+    other_keys = character(),
     compactify = NULL,
     clobberable_versions_start = NA,
     .versions_end = max_version_with_row_in(x), ...,
@@ -518,11 +511,10 @@ as_epi_archive <- function(
   time_type <- guess_time_type(x$time_value)
 
   validate_epi_archive(
-    x, other_keys, additional_metadata,
-    compactify, clobberable_versions_start, versions_end
+    x, other_keys, compactify, clobberable_versions_start, versions_end
   )
   new_epi_archive(
-    x, geo_type, time_type, other_keys, additional_metadata,
+    x, geo_type, time_type, other_keys,
     compactify, clobberable_versions_start, versions_end
   )
 }
@@ -551,7 +543,7 @@ print.epi_archive <- function(x, ..., class = TRUE, methods = TRUE) {
     c(
       ">" = if (class) "An `epi_archive` object, with metadata:",
       "i" = if (length(setdiff(key(x$DT), c("geo_value", "time_value", "version"))) > 0) {
-        "Non-standard DT keys: {setdiff(key(x$DT), c('geo_value', 'time_value', 'version'))}"
+        "Other DT keys: {setdiff(key(x$DT), c('geo_value', 'time_value', 'version'))}"
       },
       "i" = if (nrow(x$DT) != 0L) {
         "Min/max time values: {min(x$DT$time_value)} / {max(x$DT$time_value)}"
@@ -687,7 +679,8 @@ print.epi_archive <- function(x, ..., class = TRUE, methods = TRUE) {
 #' @export
 #'
 #' @aliases grouped_epi_archive
-group_by.epi_archive <- function(.data, ..., .add = FALSE, .drop = dplyr::group_by_drop_default(.data)) {
+group_by.epi_archive <- function(.data, ..., .add = FALSE,
+                                 .drop = dplyr::group_by_drop_default(.data)) {
   # `add` makes no difference; this is an ungrouped `epi_archive`.
   detailed_mutate <- epix_detailed_restricted_mutate(.data, ...)
   assert_logical(.drop)
diff --git a/R/epi_df.R b/R/epi_df.R
index 56424bf0..fedcff55 100644
--- a/R/epi_df.R
+++ b/R/epi_df.R
@@ -127,7 +127,7 @@
 #'   dplyr::rename(geo_value = state, time_value = reported_date) %>%
 #'   as_epi_df(
 #'     as_of = "2020-06-03",
-#'     additional_metadata = list(other_keys = "pol")
+#'     other_keys = "pol"
 #'   )
 #'
 #' attr(ex2, "metadata")
@@ -146,47 +146,46 @@
 #'     state = rep("MA", 6),
 #'     pol = rep(c("blue", "swing", "swing"), each = 2)
 #'   ) %>%
-#'   # the 2 extra keys we added have to be specified in the other_keys
-#'   # component of additional_metadata.
-#'   as_epi_df(additional_metadata = list(other_keys = c("state", "pol")))
+#'   as_epi_df(other_keys = c("state", "pol"))
 #'
 #' attr(ex3, "metadata")
 NULL
 
-#' Create an `epi_df` object
-#'
-#' @rdname epi_df
-#' @param geo_type DEPRECATED Has no effect. Geo value type is inferred from the
-#' location column and set to "custom" if not recognized.
-#' @param time_type DEPRECATED Has no effect. Time value type inferred from the time
-#' column and set to "custom" if not recognized. Unpredictable behavior may result
-#' if the time type is not recognized.
+#' @describeIn epi_df Lower-level constructor for `epi_df` object
+#' @order 2
+#' @param geo_type `r lifecycle::badge("deprecated")` in `as_epi_df()`, has no
+#'   effect; the geo value type is inferred from the location column and set to
+#'   "custom" if not recognized. In `new_epi_df()`, should be set to the same
+#'   value that would be inferred.
+#' @param time_type `r lifecycle::badge("deprecated")` in `as_epi_df()`, has no
+#'   effect: the time value type inferred from the time column and set to
+#'   "custom" if not recognized. Unpredictable behavior may result if the time
+#'   type is not recognized. In `new_epi_df()`, should be set to the same value
+#'   that would be inferred.
 #' @param as_of Time value representing the time at which the given data were
 #'   available. For example, if `as_of` is January 31, 2022, then the `epi_df`
 #'   object that is created would represent the most up-to-date version of the
 #'   data available as of January 31, 2022. If the `as_of` argument is missing,
 #'   then the current day-time will be used.
-#' @param additional_metadata List of additional metadata to attach to the
-#'   `epi_df` object. The metadata will have `geo_type`, `time_type`, and
-#'   `as_of` fields; named entries from the passed list will be included as
-#'   well. If your tibble has additional keys, be sure to specify them as a
-#'   character vector in the `other_keys` component of `additional_metadata`.
+#' @param other_keys If your tibble has additional keys, be sure to specify them
+#'   as a character vector here (typical examples are "age" or sub-geographies).
 #' @param ... Additional arguments passed to methods.
 #' @return An `epi_df` object.
 #'
 #' @export
-new_epi_df <- function(x = tibble::tibble(), geo_type, time_type, as_of,
-                       additional_metadata = list()) {
+new_epi_df <- function(x = tibble::tibble(geo_value = character(), time_value = as.Date(integer())),
+                       geo_type, time_type, as_of,
+                       other_keys = character(), ...) {
   # Define metadata fields
   metadata <- list()
   metadata$geo_type <- geo_type
   metadata$time_type <- time_type
   metadata$as_of <- as_of
-  metadata <- c(metadata, additional_metadata)
+  metadata$other_keys <- other_keys
 
   # Reorder columns (geo_value, time_value, ...)
   if (sum(dim(x)) != 0) {
-    cols_to_put_first <- c("geo_value", "time_value")
+    cols_to_put_first <- c("geo_value", "time_value", other_keys)
     x <- x[, c(
       cols_to_put_first,
       # All other columns
@@ -200,7 +199,8 @@ new_epi_df <- function(x = tibble::tibble(), geo_type, time_type, as_of,
   return(x)
 }
 
-#' @rdname epi_df
+#' @describeIn epi_df The preferred way of constructing `epi_df`s
+#' @order 1
 #' @param x An `epi_df`, `data.frame`, [tibble::tibble], or [tsibble::tsibble]
 #'   to be converted
 #' @param ... used for specifying column names, as in [`dplyr::rename`]. For
@@ -211,6 +211,7 @@ as_epi_df <- function(x, ...) {
 }
 
 #' @rdname epi_df
+#' @order 1
 #' @method as_epi_df epi_df
 #' @export
 as_epi_df.epi_df <- function(x, ...) {
@@ -218,17 +219,18 @@ as_epi_df.epi_df <- function(x, ...) {
 }
 
 #' @rdname epi_df
-#' @method as_epi_df tbl_df
+#' @order 1
 #' @importFrom rlang .data
 #' @importFrom tidyselect any_of
 #' @importFrom cli cli_inform
+#' @method as_epi_df tbl_df
 #' @export
 as_epi_df.tbl_df <- function(
     x,
     geo_type = deprecated(),
     time_type = deprecated(),
     as_of,
-    additional_metadata = list(),
+    other_keys = character(),
     ...) {
   # possible standard substitutions for time_value
   x <- rename(x, ...)
@@ -274,29 +276,28 @@ as_epi_df.tbl_df <- function(
     } # Use the current day-time
   }
 
-  assert_list(additional_metadata)
-  additional_metadata[["other_keys"]] <- additional_metadata[["other_keys"]] %||% character(0L)
-  new_epi_df(x, geo_type, time_type, as_of, additional_metadata)
+  assert_character(other_keys)
+  new_epi_df(x, geo_type, time_type, as_of, other_keys)
 }
 
-#' @method as_epi_df data.frame
 #' @rdname epi_df
+#' @order 1
+#' @method as_epi_df data.frame
 #' @export
-as_epi_df.data.frame <- function(x, as_of, additional_metadata = list(), ...) {
-  as_epi_df.tbl_df(x = tibble::as_tibble(x), as_of = as_of, additional_metadata = additional_metadata, ...)
+as_epi_df.data.frame <- function(x, as_of, other_keys = character(), ...) {
+  as_epi_df.tbl_df(x = tibble::as_tibble(x), as_of = as_of, other_keys = other_keys, ...)
 }
 
-#' @method as_epi_df tbl_ts
 #' @rdname epi_df
+#' @order 1
+#' @method as_epi_df tbl_ts
 #' @export
-as_epi_df.tbl_ts <- function(x, as_of, additional_metadata = list(), ...) {
+as_epi_df.tbl_ts <- function(x, as_of, other_keys = character(), ...) {
   tsibble_other_keys <- setdiff(tsibble::key_vars(x), "geo_value")
-  if (length(tsibble_other_keys) != 0) {
-    additional_metadata$other_keys <- unique(
-      c(additional_metadata$other_keys, tsibble_other_keys)
-    )
+  if (length(tsibble_other_keys) > 0) {
+    other_keys <- unique(c(other_keys, tsibble_other_keys))
   }
-  as_epi_df.tbl_df(x = tibble::as_tibble(x), as_of = as_of, additional_metadata = additional_metadata, ...)
+  as_epi_df.tbl_df(x = tibble::as_tibble(x), as_of = as_of, other_keys = other_keys, ...)
 }
 
 #' Test for `epi_df` format
diff --git a/R/methods-epi_archive.R b/R/methods-epi_archive.R
index 96d14d9b..dae7b243 100644
--- a/R/methods-epi_archive.R
+++ b/R/methods-epi_archive.R
@@ -65,7 +65,6 @@ epix_as_of <- function(x, max_version, min_time_value = -Inf, all_versions = FAL
     key(x$DT),
     c("geo_value", "time_value", "version")
   )
-  if (length(other_keys) == 0) other_keys <- NULL
 
   # Check a few things on max_version
   if (!identical(class(max_version), class(x$DT$version))) {
@@ -112,10 +111,7 @@ epix_as_of <- function(x, max_version, min_time_value = -Inf, all_versions = FAL
     dplyr::select(-"version") %>%
     as_epi_df(
       as_of = max_version,
-      additional_metadata = c(
-        x$additional_metadata,
-        list(other_keys = other_keys)
-      )
+      other_keys = other_keys
     )
 
   return(as_of_epi_df)
@@ -240,9 +236,8 @@ epix_fill_through_version <- function(x, fill_versions_end,
 #'   Default here is `TRUE`.
 #' @return the resulting `epi_archive`
 #'
-#' @details In all cases, `additional_metadata` will be an empty list, and
-#'   `clobberable_versions_start` will be set to the earliest version that could
-#'   be clobbered in either input archive.
+#' @details In all cases, `clobberable_versions_start` will be set to the
+#'   earliest version that could be clobbered in either input archive.
 #'
 #' @examples
 #' # Example 1
@@ -331,18 +326,6 @@ epix_merge <- function(x, y,
     cli_abort("`x` and `y` must share data type on their `time_value` column.")
   }
 
-  if (length(x$additional_metadata) != 0L) {
-    cli_warn("x$additional_metadata won't appear in merge result",
-      class = "epiprocess__epix_merge_ignores_additional_metadata"
-    )
-  }
-  if (length(y$additional_metadata) != 0L) {
-    cli_warn("y$additional_metadata won't appear in merge result",
-      class = "epiprocess__epix_merge_ignores_additional_metadata"
-    )
-  }
-  result_additional_metadata <- list()
-
   result_clobberable_versions_start <-
     if (all(is.na(c(x$clobberable_versions_start, y$clobberable_versions_start)))) {
       NA # (any type of NA is fine here)
@@ -508,7 +491,6 @@ epix_merge <- function(x, y,
   return(as_epi_archive(
     result_dt[], # clear data.table internal invisibility flag if set
     other_keys = setdiff(key(result_dt), c("geo_value", "time_value", "version")),
-    additional_metadata = result_additional_metadata,
     # It'd probably be better to pre-compactify before the merge, and might be
     # guaranteed not to be necessary to compactify the merge result if the
     # inputs are already compactified, but at time of writing we don't have
diff --git a/R/methods-epi_df.R b/R/methods-epi_df.R
index 1876ab46..4e74fd1c 100644
--- a/R/methods-epi_df.R
+++ b/R/methods-epi_df.R
@@ -63,6 +63,10 @@ print.epi_df <- function(x, ...) {
   )
   cat(sprintf("* %-9s = %s\n", "geo_type", attributes(x)$metadata$geo_type))
   cat(sprintf("* %-9s = %s\n", "time_type", attributes(x)$metadata$time_type))
+  ok <- attributes(x)$metadata$other_keys
+  if (length(ok) > 0) {
+    cat(sprintf("* %-9s = %s\n", "other_keys", paste(ok, collapse = ", ")))
+  }
   cat(sprintf("* %-9s = %s\n", "as_of", attributes(x)$metadata$as_of))
   # Conditional output (silent if attribute is NULL):
   cat(sprintf("* %-9s = %s\n", "decay_to_tibble", attr(x, "decay_to_tibble")))
@@ -86,6 +90,10 @@ print.epi_df <- function(x, ...) {
 summary.epi_df <- function(object, ...) {
   cat("An `epi_df` x, with metadata:\n")
   cat(sprintf("* %-9s = %s\n", "geo_type", attributes(object)$metadata$geo_type))
+  ok <- attributes(object)$metadata$other_keys
+  if (length(ok) > 0) {
+    cat(sprintf("* %-9s = %s\n", "other_keys", paste(ok, collapse = ", ")))
+  }
   cat(sprintf("* %-9s = %s\n", "as_of", attributes(object)$metadata$as_of))
   cat("----------\n")
   cat(sprintf("* %-27s = %s\n", "min time value", min(object$time_value)))
@@ -206,12 +214,13 @@ dplyr_row_slice.epi_df <- function(data, i, ...) {
 `names<-.epi_df` <- function(x, value) {
   old_names <- names(x)
   old_metadata <- attr(x, "metadata")
-  old_other_keys <- old_metadata[["other_keys"]]
-  new_other_keys <- value[match(old_other_keys, old_names)]
   new_metadata <- old_metadata
-  new_metadata[["other_keys"]] <- new_other_keys
+  old_other_keys <- old_metadata[["other_keys"]]
+  if (!is.null(old_other_keys)) {
+    new_other_keys <- value[match(old_other_keys, old_names)]
+    new_metadata[["other_keys"]] <- new_other_keys
+  }
   result <- reclass(NextMethod(), new_metadata)
-  # decay to non-`epi_df` if needed:
   dplyr::dplyr_reconstruct(result, result)
 }
 
diff --git a/R/slide.R b/R/slide.R
index 91cebd2b..1bbd04b7 100644
--- a/R/slide.R
+++ b/R/slide.R
@@ -419,7 +419,7 @@ epi_slide <- function(
 #'   ungroup()
 epi_slide_opt <- function(
     .x, .col_names, .f, ...,
-    .window_size = 0, .align = c("right", "center", "left"),
+    .window_size = 1, .align = c("right", "center", "left"),
     .ref_time_values = NULL, .all_rows = FALSE) {
   assert_class(.x, "epi_df")
 
@@ -745,7 +745,7 @@ epi_slide_opt <- function(
 #'   ungroup()
 epi_slide_mean <- function(
     .x, .col_names, ...,
-    .window_size = 0, .align = c("right", "center", "left"),
+    .window_size = 1, .align = c("right", "center", "left"),
     .ref_time_values = NULL, .all_rows = FALSE) {
   # Argument deprecation handling
   provided_args <- rlang::call_args_names(rlang::call_match())
@@ -828,7 +828,7 @@ epi_slide_mean <- function(
 #'   ungroup()
 epi_slide_sum <- function(
     .x, .col_names, ...,
-    .window_size = 0, .align = c("right", "center", "left"),
+    .window_size = 1, .align = c("right", "center", "left"),
     .ref_time_values = NULL, .all_rows = FALSE) {
   # Argument deprecation handling
   provided_args <- rlang::call_args_names(rlang::call_match())
diff --git a/R/sysdata.rda b/R/sysdata.rda
index d100711d..8e8dc5ff 100644
Binary files a/R/sysdata.rda and b/R/sysdata.rda differ
diff --git a/data/incidence_num_outlier_example.rda b/data/incidence_num_outlier_example.rda
index e898b5ea..96288982 100644
Binary files a/data/incidence_num_outlier_example.rda and b/data/incidence_num_outlier_example.rda differ
diff --git a/data/jhu_csse_county_level_subset.rda b/data/jhu_csse_county_level_subset.rda
index aca0983d..bc31b493 100644
Binary files a/data/jhu_csse_county_level_subset.rda and b/data/jhu_csse_county_level_subset.rda differ
diff --git a/data/jhu_csse_daily_subset.rda b/data/jhu_csse_daily_subset.rda
index 12fd5f15..e4dbdc9f 100644
Binary files a/data/jhu_csse_daily_subset.rda and b/data/jhu_csse_daily_subset.rda differ
diff --git a/man/epi_archive.Rd b/man/epi_archive.Rd
index dee4cbaf..a5055f4e 100644
--- a/man/epi_archive.Rd
+++ b/man/epi_archive.Rd
@@ -12,7 +12,6 @@ new_epi_archive(
   geo_type,
   time_type,
   other_keys,
-  additional_metadata,
   compactify,
   clobberable_versions_start,
   versions_end,
@@ -22,7 +21,6 @@ new_epi_archive(
 validate_epi_archive(
   x,
   other_keys,
-  additional_metadata,
   compactify,
   clobberable_versions_start,
   versions_end
@@ -32,8 +30,7 @@ as_epi_archive(
   x,
   geo_type = deprecated(),
   time_type = deprecated(),
-  other_keys = character(0L),
-  additional_metadata = list(),
+  other_keys = character(),
   compactify = NULL,
   clobberable_versions_start = NA,
   .versions_end = max_version_with_row_in(x),
@@ -54,11 +51,8 @@ if the time type is not recognized.}
 
 \item{other_keys}{Character vector specifying the names of variables in \code{x}
 that should be considered key variables (in the language of \code{data.table})
-apart from "geo_value", "time_value", and "version".}
-
-\item{additional_metadata}{List of additional metadata to attach to the
-\code{epi_archive} object. The metadata will have the \code{geo_type} field; named
-entries from the passed list or will be included as well.}
+apart from "geo_value", "time_value", and "version". Typical examples
+are "age" or more granular geographies.}
 
 \item{compactify}{Optional; Boolean. \code{TRUE} will remove some
 redundant rows, \code{FALSE} will not, and missing or \code{NULL} will remove
@@ -136,7 +130,8 @@ object:
 \itemize{
 \item \code{geo_type}: the type for the geo values.
 \item \code{time_type}: the type for the time values.
-\item \code{additional_metadata}: list of additional metadata for the data archive.
+\item \code{other_keys}: any additional keys as a character vector.
+Typical examples are "age" or sub-geographies.
 }
 
 While this metadata is not protected, it is generally recommended to treat it
diff --git a/man/epi_df.Rd b/man/epi_df.Rd
index dcda0872..38f923c5 100644
--- a/man/epi_df.Rd
+++ b/man/epi_df.Rd
@@ -1,23 +1,15 @@
 % Generated by roxygen2: do not edit by hand
 % Please edit documentation in R/epi_df.R
-\name{epi_df}
-\alias{epi_df}
-\alias{new_epi_df}
+\name{as_epi_df}
 \alias{as_epi_df}
 \alias{as_epi_df.epi_df}
 \alias{as_epi_df.tbl_df}
 \alias{as_epi_df.data.frame}
 \alias{as_epi_df.tbl_ts}
+\alias{new_epi_df}
+\alias{epi_df}
 \title{\code{epi_df} object}
 \usage{
-new_epi_df(
-  x = tibble::tibble(),
-  geo_type,
-  time_type,
-  as_of,
-  additional_metadata = list()
-)
-
 as_epi_df(x, ...)
 
 \method{as_epi_df}{epi_df}(x, ...)
@@ -27,24 +19,39 @@ as_epi_df(x, ...)
   geo_type = deprecated(),
   time_type = deprecated(),
   as_of,
-  additional_metadata = list(),
+  other_keys = character(),
   ...
 )
 
-\method{as_epi_df}{data.frame}(x, as_of, additional_metadata = list(), ...)
+\method{as_epi_df}{data.frame}(x, as_of, other_keys = character(), ...)
+
+\method{as_epi_df}{tbl_ts}(x, as_of, other_keys = character(), ...)
 
-\method{as_epi_df}{tbl_ts}(x, as_of, additional_metadata = list(), ...)
+new_epi_df(
+  x = tibble::tibble(geo_value = character(), time_value = as.Date(integer())),
+  geo_type,
+  time_type,
+  as_of,
+  other_keys = character(),
+  ...
+)
 }
 \arguments{
 \item{x}{An \code{epi_df}, \code{data.frame}, \link[tibble:tibble]{tibble::tibble}, or \link[tsibble:tsibble]{tsibble::tsibble}
 to be converted}
 
-\item{geo_type}{DEPRECATED Has no effect. Geo value type is inferred from the
-location column and set to "custom" if not recognized.}
+\item{...}{Additional arguments passed to methods.}
 
-\item{time_type}{DEPRECATED Has no effect. Time value type inferred from the time
-column and set to "custom" if not recognized. Unpredictable behavior may result
-if the time type is not recognized.}
+\item{geo_type}{\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} in \code{as_epi_df()}, has no
+effect; the geo value type is inferred from the location column and set to
+"custom" if not recognized. In \code{new_epi_df()}, should be set to the same
+value that would be inferred.}
+
+\item{time_type}{\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} in \code{as_epi_df()}, has no
+effect: the time value type inferred from the time column and set to
+"custom" if not recognized. Unpredictable behavior may result if the time
+type is not recognized. In \code{new_epi_df()}, should be set to the same value
+that would be inferred.}
 
 \item{as_of}{Time value representing the time at which the given data were
 available. For example, if \code{as_of} is January 31, 2022, then the \code{epi_df}
@@ -52,14 +59,8 @@ object that is created would represent the most up-to-date version of the
 data available as of January 31, 2022. If the \code{as_of} argument is missing,
 then the current day-time will be used.}
 
-\item{additional_metadata}{List of additional metadata to attach to the
-\code{epi_df} object. The metadata will have \code{geo_type}, \code{time_type}, and
-\code{as_of} fields; named entries from the passed list will be included as
-well. If your tibble has additional keys, be sure to specify them as a
-character vector in the \code{other_keys} component of \code{additional_metadata}.}
-
-\item{...}{used for specifying column names, as in \code{\link[dplyr:rename]{dplyr::rename}}. For
-example, \verb{geo_value = STATEFP, time_value = end_date}.}
+\item{other_keys}{If your tibble has additional keys, be sure to specify them
+as a character vector here (typical examples are "age" or sub-geographies).}
 }
 \value{
 An \code{epi_df} object.
@@ -117,6 +118,13 @@ data versioning works in the \code{epiprocess} package (including how to
 generate \code{epi_df} objects, as data snapshots, from an \code{epi_archive}
 object).
 }
+\section{Functions}{
+\itemize{
+\item \code{as_epi_df()}: The preferred way of constructing \code{epi_df}s
+
+\item \code{new_epi_df()}: Lower-level constructor for \code{epi_df} object
+
+}}
 \section{Geo Types}{
 
 The following geo types are recognized in an \code{epi_df}.
@@ -200,7 +208,7 @@ ex2 <- ex2_input \%>\%
   dplyr::rename(geo_value = state, time_value = reported_date) \%>\%
   as_epi_df(
     as_of = "2020-06-03",
-    additional_metadata = list(other_keys = "pol")
+    other_keys = "pol"
   )
 
 attr(ex2, "metadata")
@@ -219,9 +227,7 @@ ex3 <- ex3_input \%>\%
     state = rep("MA", 6),
     pol = rep(c("blue", "swing", "swing"), each = 2)
   ) \%>\%
-  # the 2 extra keys we added have to be specified in the other_keys
-  # component of additional_metadata.
-  as_epi_df(additional_metadata = list(other_keys = c("state", "pol")))
+  as_epi_df(other_keys = c("state", "pol"))
 
 attr(ex3, "metadata")
 }
diff --git a/man/epi_slide_mean.Rd b/man/epi_slide_mean.Rd
index 820292ad..09faefb6 100644
--- a/man/epi_slide_mean.Rd
+++ b/man/epi_slide_mean.Rd
@@ -8,7 +8,7 @@ epi_slide_mean(
   .x,
   .col_names,
   ...,
-  .window_size = 0,
+  .window_size = 1,
   .align = c("right", "center", "left"),
   .ref_time_values = NULL,
   .all_rows = FALSE
diff --git a/man/epi_slide_opt.Rd b/man/epi_slide_opt.Rd
index 7fc54b7e..dcaab3f8 100644
--- a/man/epi_slide_opt.Rd
+++ b/man/epi_slide_opt.Rd
@@ -10,7 +10,7 @@ epi_slide_opt(
   .col_names,
   .f,
   ...,
-  .window_size = 0,
+  .window_size = 1,
   .align = c("right", "center", "left"),
   .ref_time_values = NULL,
   .all_rows = FALSE
diff --git a/man/epi_slide_sum.Rd b/man/epi_slide_sum.Rd
index 3c7baedc..0c83c432 100644
--- a/man/epi_slide_sum.Rd
+++ b/man/epi_slide_sum.Rd
@@ -8,7 +8,7 @@ epi_slide_sum(
   .x,
   .col_names,
   ...,
-  .window_size = 0,
+  .window_size = 1,
   .align = c("right", "center", "left"),
   .ref_time_values = NULL,
   .all_rows = FALSE
diff --git a/man/epix_merge.Rd b/man/epix_merge.Rd
index 43f53c33..564a1fdc 100644
--- a/man/epix_merge.Rd
+++ b/man/epix_merge.Rd
@@ -46,9 +46,8 @@ clobberable versions). If the \code{versions_end} values differ, the \code{sync}
 parameter controls what is done.
 }
 \details{
-In all cases, \code{additional_metadata} will be an empty list, and
-\code{clobberable_versions_start} will be set to the earliest version that could
-be clobbered in either input archive.
+In all cases, \code{clobberable_versions_start} will be set to the
+earliest version that could be clobbered in either input archive.
 }
 \examples{
 # Example 1
diff --git a/tests/testthat/test-archive.R b/tests/testthat/test-archive.R
index 7f20ddeb..1791d870 100644
--- a/tests/testthat/test-archive.R
+++ b/tests/testthat/test-archive.R
@@ -77,14 +77,6 @@ test_that("other_keys cannot contain names geo_value, time_value or version", {
   )
 })
 
-test_that("Warning thrown when other_metadata contains overlapping names with geo_type field", {
-  expect_warning(as_epi_archive(archive_data, additional_metadata = list(geo_type = 1), compactify = FALSE),
-    regexp = "`additional_metadata` names overlap with existing metadata fields"
-  )
-  expect_warning(as_epi_archive(archive_data, additional_metadata = list(time_type = 1), compactify = FALSE),
-    regexp = "`additional_metadata` names overlap with existing metadata fields"
-  )
-})
 
 test_that("epi_archives are correctly instantiated with a variety of data types", {
   d <- as.Date("2020-01-01")
@@ -98,22 +90,22 @@ test_that("epi_archives are correctly instantiated with a variety of data types"
 
   ea1 <- as_epi_archive(df, compactify = FALSE)
   expect_equal(key(ea1$DT), c("geo_value", "time_value", "version"))
-  expect_equal(ea1$additional_metadata, list())
+  expect_null(ea1$additional_metadata)
 
-  ea2 <- as_epi_archive(df, other_keys = "value", additional_metadata = list(value = df$value), compactify = FALSE)
+  ea2 <- as_epi_archive(df, other_keys = "value", compactify = FALSE)
   expect_equal(key(ea2$DT), c("geo_value", "time_value", "value", "version"))
-  expect_equal(ea2$additional_metadata, list(value = df$value))
+  expect_null(ea2$additional_metadata)
 
   # Tibble
   tib <- tibble::tibble(df, code = "x")
 
   ea3 <- as_epi_archive(tib, compactify = FALSE)
   expect_equal(key(ea3$DT), c("geo_value", "time_value", "version"))
-  expect_equal(ea3$additional_metadata, list())
+  expect_null(ea3$additional_metadata)
 
-  ea4 <- as_epi_archive(tib, other_keys = "code", additional_metadata = list(value = df$value), compactify = FALSE)
+  ea4 <- as_epi_archive(tib, other_keys = "code", compactify = FALSE)
   expect_equal(key(ea4$DT), c("geo_value", "time_value", "code", "version"))
-  expect_equal(ea4$additional_metadata, list(value = df$value))
+  expect_null(ea4$additional_metadata)
 
   # Keyed data.table
   kdt <- data.table::data.table(
@@ -128,12 +120,12 @@ test_that("epi_archives are correctly instantiated with a variety of data types"
   ea5 <- as_epi_archive(kdt, compactify = FALSE)
   # Key from data.table isn't absorbed when as_epi_archive is used
   expect_equal(key(ea5$DT), c("geo_value", "time_value", "version"))
-  expect_equal(ea5$additional_metadata, list())
+  expect_null(ea5$additional_metadata)
 
-  ea6 <- as_epi_archive(kdt, other_keys = "value", additional_metadata = list(value = df$value), compactify = FALSE)
+  ea6 <- as_epi_archive(kdt, other_keys = "value", compactify = FALSE)
   # Mismatched keys, but the one from as_epi_archive overrides
   expect_equal(key(ea6$DT), c("geo_value", "time_value", "value", "version"))
-  expect_equal(ea6$additional_metadata, list(value = df$value))
+  expect_null(ea6$additional_metadata)
 
   # Unkeyed data.table
   udt <- data.table::data.table(
@@ -146,11 +138,11 @@ test_that("epi_archives are correctly instantiated with a variety of data types"
 
   ea7 <- as_epi_archive(udt, compactify = FALSE)
   expect_equal(key(ea7$DT), c("geo_value", "time_value", "version"))
-  expect_equal(ea7$additional_metadata, list())
+  expect_null(ea7$additional_metadata)
 
-  ea8 <- as_epi_archive(udt, other_keys = "code", additional_metadata = list(value = df$value), compactify = FALSE)
+  ea8 <- as_epi_archive(udt, other_keys = "code", compactify = FALSE)
   expect_equal(key(ea8$DT), c("geo_value", "time_value", "code", "version"))
-  expect_equal(ea8$additional_metadata, list(value = df$value))
+  expect_null(ea8$additional_metadata)
 
   # epi_df
   edf1 <- jhu_csse_daily_subset %>%
@@ -159,11 +151,11 @@ test_that("epi_archives are correctly instantiated with a variety of data types"
 
   ea9 <- as_epi_archive(edf1, compactify = FALSE)
   expect_equal(key(ea9$DT), c("geo_value", "time_value", "version"))
-  expect_equal(ea9$additional_metadata, list())
+  expect_null(ea9$additional_metadata)
 
-  ea10 <- as_epi_archive(edf1, other_keys = "code", additional_metadata = list(value = df$value), compactify = FALSE)
+  ea10 <- as_epi_archive(edf1, other_keys = "code", compactify = FALSE)
   expect_equal(key(ea10$DT), c("geo_value", "time_value", "code", "version"))
-  expect_equal(ea10$additional_metadata, list(value = df$value))
+  expect_null(ea10$additional_metadata)
 
   # Keyed epi_df
   edf2 <- data.frame(
@@ -176,15 +168,15 @@ test_that("epi_archives are correctly instantiated with a variety of data types"
     cases = 1:20,
     misc = "USA"
   ) %>%
-    as_epi_df(additional_metadata = list(other_keys = "misc"))
+    as_epi_df(other_keys = "misc")
 
   ea11 <- as_epi_archive(edf2, compactify = FALSE)
   expect_equal(key(ea11$DT), c("geo_value", "time_value", "version"))
-  expect_equal(ea11$additional_metadata, list())
+  expect_null(ea11$additional_metadata)
 
-  ea12 <- as_epi_archive(edf2, other_keys = "misc", additional_metadata = list(value = df$misc), compactify = FALSE)
+  ea12 <- as_epi_archive(edf2, other_keys = "misc", compactify = FALSE)
   expect_equal(key(ea12$DT), c("geo_value", "time_value", "misc", "version"))
-  expect_equal(ea12$additional_metadata, list(value = df$misc))
+  expect_null(ea12$additional_metadata)
 })
 
 test_that("`epi_archive` rejects nonunique keys", {
diff --git a/tests/testthat/test-arrange-canonical.R b/tests/testthat/test-arrange-canonical.R
index ec42feac..939d2f32 100644
--- a/tests/testthat/test-arrange-canonical.R
+++ b/tests/testthat/test-arrange-canonical.R
@@ -7,10 +7,12 @@ test_that("canonical arrangement works", {
   )
   expect_error(arrange_canonical(tib))
 
-  tib <- tib %>% as_epi_df(additional_metadata = list(other_keys = "demo_grp"))
-  expect_equal(names(tib), c("geo_value", "time_value", "x", "demo_grp"))
+  tib <- tib %>% as_epi_df(other_keys = "demo_grp")
+  expect_equal(names(tib), c("geo_value", "time_value", "demo_grp", "x"))
 
-  tib_sorted <- arrange_canonical(tib)
+  tib_cols_shuffled <- tib %>% select(geo_value, time_value, x, demo_grp)
+
+  tib_sorted <- arrange_canonical(tib_cols_shuffled)
   expect_equal(names(tib_sorted), c("geo_value", "time_value", "demo_grp", "x"))
   expect_equal(tib_sorted$geo_value, rep(c("ca", "ga"), each = 4))
   expect_equal(tib_sorted$time_value, c(1, 1, 2, 2, 1, 1, 2, 2))
diff --git a/tests/testthat/test-epi_df.R b/tests/testthat/test-epi_df.R
index a49855aa..2444a87a 100644
--- a/tests/testthat/test-epi_df.R
+++ b/tests/testthat/test-epi_df.R
@@ -23,8 +23,7 @@ test_that("new_epi_df works as intended", {
   expect_true(lubridate::is.POSIXt(attributes(epi_tib)$metadata$as_of))
 })
 
-test_that("as_epi_df errors when additional_metadata is not a list", {
-  # This is the 3rd example from as_epi_df
+test_that("as_epi_df errors for non-character other_keys", {
   ex_input <- jhu_csse_county_level_subset %>%
     dplyr::filter(time_value > "2021-12-01", state_name == "Massachusetts") %>%
     dplyr::slice_tail(n = 6) %>%
@@ -35,9 +34,10 @@ test_that("as_epi_df errors when additional_metadata is not a list", {
     )
 
   expect_error(
-    as_epi_df(ex_input, additional_metadata = c(other_keys = "state", "pol")),
-    "Must be of type 'list', not 'character'."
+    as_epi_df(ex_input, other_keys = list()),
+    "Must be of type 'character'"
   )
+  expect_silent(as_epi_df(ex_input, other_keys = c("state", "pol")))
 })
 
 test_that("as_epi_df works for nonstandard input", {
@@ -81,7 +81,7 @@ tib <- tibble::tibble(
   time_value = rep(seq(as.Date("2020-01-01"), by = 1, length.out = 5), times = 2),
   geo_value = rep(c("ca", "hi"), each = 5)
 )
-epi_tib <- epiprocess::as_epi_df(tib)
+epi_tib <- as_epi_df(tib)
 test_that("grouped epi_df maintains type for select", {
   grouped_epi <- epi_tib %>% group_by(geo_value)
   selected_df <- grouped_epi %>% select(-y)
@@ -108,9 +108,7 @@ test_that("grouped epi_df handles extra keys correctly", {
     geo_value = rep(c("ca", "hi"), each = 5),
     extra_key = rep(seq(as.Date("2020-01-01"), by = 1, length.out = 5), times = 2)
   )
-  epi_tib <- epiprocess::as_epi_df(tib,
-    additional_metadata = list(other_keys = "extra_key")
-  )
+  epi_tib <- as_epi_df(tib, other_keys = "extra_key")
   grouped_epi <- epi_tib %>% group_by(geo_value)
   selected_df <- grouped_epi %>% select(-extra_key)
   expect_true(inherits(selected_df, "epi_df"))
diff --git a/tests/testthat/test-epix_merge.R b/tests/testthat/test-epix_merge.R
index c285ad39..5b3de284 100644
--- a/tests/testthat/test-epix_merge.R
+++ b/tests/testthat/test-epix_merge.R
@@ -177,26 +177,6 @@ test_that("epix_merge forbids and warns on metadata and naming issues", {
     ),
     regexp = "overlapping.*names"
   )
-  expect_warning(
-    epix_merge(
-      as_epi_archive(tibble::tibble(geo_value = "ak", time_value = test_date, version = test_date + 1L, x_value = 1L),
-        additional_metadata = list("updates_fetched" = lubridate::ymd_hms("2022-05-01 16:00:00", tz = "UTC"))
-      ),
-      as_epi_archive(tibble::tibble(geo_value = "ak", time_value = test_date, version = test_date + 1L, y_value = 2L))
-    ),
-    regexp = "x\\$additional_metadata",
-    class = "epiprocess__epix_merge_ignores_additional_metadata"
-  )
-  expect_warning(
-    epix_merge(
-      as_epi_archive(tibble::tibble(geo_value = "ak", time_value = test_date, version = test_date + 1L, x_value = 1L)),
-      as_epi_archive(tibble::tibble(geo_value = "ak", time_value = test_date, version = test_date + 1L, y_value = 2L),
-        additional_metadata = list("updates_fetched" = lubridate::ymd_hms("2022-05-01 16:00:00", tz = "UTC"))
-      )
-    ),
-    regexp = "y\\$additional_metadata",
-    class = "epiprocess__epix_merge_ignores_additional_metadata"
-  )
 })
 
 # use `local` to prevent accidentally using the x, y, xy bindings here
diff --git a/tests/testthat/test-grouped_epi_archive.R b/tests/testthat/test-grouped_epi_archive.R
index 4d1c1468..6ae009ca 100644
--- a/tests/testthat/test-grouped_epi_archive.R
+++ b/tests/testthat/test-grouped_epi_archive.R
@@ -80,7 +80,7 @@ test_that("Grouping, regrouping, and ungrouping archives works as intended", {
         time_value = as.Date(time_value)
       ) %>%
       # as_epi_df(as_of = as.Date("2000-01-03"),
-      #           additional_metadata = list(other_keys = "age_group")) %>%
+      #           other_keys = "age_group") %>%
       # # put back in expected order; see issue #166:
       # select(geo_value, age_group, time_value, s) %>%
       group_by(geo_value, age_group, .drop = FALSE)
diff --git a/tests/testthat/test-methods-epi_df.R b/tests/testthat/test-methods-epi_df.R
index e28e23de..bef7f680 100644
--- a/tests/testthat/test-methods-epi_df.R
+++ b/tests/testthat/test-methods-epi_df.R
@@ -10,8 +10,7 @@ toy_epi_df <- tibble::tibble(
   indic_var1 = as.factor(rep(1:2, times = 5)),
   indic_var2 = as.factor(rep(letters[1:5], times = 2))
 ) %>% as_epi_df(
-  additional_metadata =
-    list(other_keys = c("indic_var1", "indic_var2"))
+  other_keys = c("indic_var1", "indic_var2")
 )
 
 att_toy <- attr(toy_epi_df, "metadata")
@@ -79,12 +78,12 @@ test_that("Subsetting drops & does not drop the epi_df class appropriately", {
   expect_identical(att_row_col_subset2$geo_type, att_toy$geo_type)
   expect_identical(att_row_col_subset2$time_type, att_toy$time_type)
   expect_identical(att_row_col_subset2$as_of, att_toy$as_of)
-  expect_identical(att_row_col_subset2$other_keys, character(0))
+  expect_identical(att_row_col_subset2$other_keys, att_toy$other_keys[1])
 })
 
 test_that("When duplicate cols in subset should abort", {
   expect_error(toy_epi_df[, c(2, 2:3, 4, 4, 4)],
-    "Duplicated column names: time_value, y",
+    "Duplicated column names: time_value, indic_var2",
     fixed = TRUE
   )
   expect_error(toy_epi_df[1:4, c(1, 2:4, 1)],
@@ -95,7 +94,7 @@ test_that("When duplicate cols in subset should abort", {
 
 test_that("Correct metadata when subset includes some of other_keys", {
   # Only include other_var of indic_var1
-  only_indic_var1 <- toy_epi_df[, 1:5]
+  only_indic_var1 <- toy_epi_df[, c(1:3, 5:6)]
   att_only_indic_var1 <- attr(only_indic_var1, "metadata")
 
   expect_true(is_epi_df(only_indic_var1))
@@ -107,7 +106,7 @@ test_that("Correct metadata when subset includes some of other_keys", {
   expect_identical(att_only_indic_var1$other_keys, att_toy$other_keys[-2])
 
   # Only include other_var of indic_var2
-  only_indic_var2 <- toy_epi_df[, c(1:4, 6)]
+  only_indic_var2 <- toy_epi_df[, c(1:2, 4:6)]
   att_only_indic_var2 <- attr(only_indic_var2, "metadata")
 
   expect_true(is_epi_df(only_indic_var2))
@@ -142,7 +141,7 @@ test_that("Grouping are dropped by `as_tibble`", {
 
 test_that("Renaming columns gives appropriate colnames and metadata", {
   edf <- tibble::tibble(geo_value = "ak", time_value = as.Date("2020-01-01"), age = 1, value = 1) %>%
-    as_epi_df(additional_metadata = list(other_keys = "age"))
+    as_epi_df(other_keys = "age")
   # renaming using base R
   renamed_edf1 <- edf %>%
     `[`(c("geo_value", "time_value", "age", "value")) %>%
@@ -151,14 +150,14 @@ test_that("Renaming columns gives appropriate colnames and metadata", {
   expect_identical(attr(renamed_edf1, "metadata")$other_keys, c("age_group"))
   # renaming using select
   renamed_edf2 <- edf %>%
-    as_epi_df(additional_metadata = list(other_keys = "age")) %>%
+    as_epi_df(other_keys = "age") %>%
     select(geo_value, time_value, age_group = age, value)
   expect_identical(renamed_edf1, renamed_edf2)
 })
 
 test_that("Renaming columns while grouped gives appropriate colnames and metadata", {
   gedf <- tibble::tibble(geo_value = "ak", time_value = as.Date("2020-01-01"), age = 1, value = 1) %>%
-    as_epi_df(additional_metadata = list(other_keys = "age")) %>%
+    as_epi_df(other_keys = "age") %>%
     group_by(geo_value)
   # renaming using base R
   renamed_gedf1 <- gedf %>%
@@ -178,7 +177,7 @@ test_that("Renaming columns while grouped gives appropriate colnames and metadat
 
 test_that("Additional `select` on `epi_df` tests", {
   edf <- tibble::tibble(geo_value = "ak", time_value = as.Date("2020-01-01"), age = 1, value = 1) %>%
-    as_epi_df(additional_metadata = list(other_keys = "age"))
+    as_epi_df(other_keys = "age")
 
   # Dropping a non-geo_value epikey column doesn't decay, though maybe it
   # should, since you'd expect that to possibly result in multiple rows per
diff --git a/tests/testthat/test-utils.R b/tests/testthat/test-utils.R
index 12e7a3f7..d18f9f48 100644
--- a/tests/testthat/test-utils.R
+++ b/tests/testthat/test-utils.R
@@ -251,8 +251,8 @@ test_that("guess_period works", {
     weekly_posixcts
   )
   # On POSIXlts:
-  daily_posixlts <- as.POSIXlt(daily_dates, tz = "US/Aleutian") + 3600
-  weekly_posixlts <- as.POSIXlt(weekly_dates, tz = "US/Aleutian") + 3600
+  daily_posixlts <- as.POSIXlt(daily_dates, tz = "UTC") + 3600
+  weekly_posixlts <- as.POSIXlt(weekly_dates, tz = "UTC") + 3600
   expect_identical(
     daily_posixlts[[1L]] + guess_period(daily_posixlts) * (seq_along(daily_posixlts) - 1L),
     daily_posixlts
diff --git a/vignettes/archive.Rmd b/vignettes/archive.Rmd
index 3d616d92..c5cc154b 100644
--- a/vignettes/archive.Rmd
+++ b/vignettes/archive.Rmd
@@ -119,7 +119,6 @@ The following pieces of metadata are included as fields in an `epi_archive`
 object:
 
 * `geo_type`: the type for the geo values.
-* `additional_metadata`: list of additional metadata for the data archive.
 
 Metadata for an `epi_archive` object `x` can be accessed (and altered) directly,
 as in `x$geo_type`, etc. Just like `as_epi_df()`, the function
diff --git a/vignettes/epiprocess.Rmd b/vignettes/epiprocess.Rmd
index 24a98505..e6c78aba 100644
--- a/vignettes/epiprocess.Rmd
+++ b/vignettes/epiprocess.Rmd
@@ -234,7 +234,7 @@ ex2 <- ex2 %>%
   rename(geo_value = state, time_value = reported_date) %>%
   as_epi_df(
     as_of = "2020-06-03",
-    additional_metadata = list(other_keys = "pol")
+    other_keys = "pol"
   )
 
 attr(ex2, "metadata")
@@ -264,12 +264,12 @@ ex3 <- ex3 %>%
     state = rep(tolower("MA"), 6),
     pol = rep(c("blue", "swing", "swing"), each = 2)
   ) %>%
-  as_epi_df(additional_metadata = list(other_keys = c("state", "pol")), as_of = as.Date("2024-03-20"))
+  as_epi_df(other_keys = c("state", "pol"), as_of = as.Date("2024-03-20"))
 
 attr(ex3, "metadata")
 ```
 
-Note that the two additional keys we added, `state` and `pol`, are specified as a character vector in the `other_keys` component of the `additional_metadata` list. They must be specified in this manner so that downstream actions on the `epi_df`, like model fitting and prediction, can recognize and use these keys.
+Note that the two additional keys we added, `state` and `pol`, are specified as a character vector in the `other_keys` argument. They must be specified in this manner so that downstream actions on the `epi_df`, like model fitting and prediction, can recognize and use these keys.
 
 Currently `other_keys` metadata in `epi_df` doesn't impact `epi_slide()`, contrary to `other_keys` in `as_epi_archive` which affects how the update data is interpreted.