diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ac52419..75883b2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -4,7 +4,6 @@ on:
   push:
     branches:
       - "main"
-      - "master"
     paths-ignore:
       - "README.md"
       - "LICENSE"
@@ -17,10 +16,11 @@ jobs:
   test:
     runs-on: ${{ matrix.os }}
     strategy:
-      fail-fast: false
+      fail-fast: ${{ github.event_name == 'pull_request' }}
       matrix:
         version:
           - "1.0"
+          - "1.6" # Long-term support (LTS) release of Julia
           - "1" # automatically expands to the latest stable 1.x release of Julia
           - nightly
         os:
@@ -33,10 +33,15 @@ jobs:
         pkg-server:
           - ""
           - "pkg.julialang.org"
-        # 32-bit Julia binaries are not available on macOS
         exclude:
+          # 32-bit Julia binaries are not available on macOS
           - os: macOS-latest
             arch: x86
+          # Only Julia 1.7+ can use the package server
+          - version: "1.0"
+            pkg-server: "pkg.julialang.org"
+          - version: "1.6"
+            pkg-server: "pkg.julialang.org"
 
     steps:
       - name: Checkout Example.jl
@@ -61,9 +66,20 @@ jobs:
       - uses: ./.github/actions/julia-buildpkg
         with:
           ignore-no-cache: true
+          localregistry: |
+            https://github.com/JuliaRegistries/General.git
         env:
           JULIA_PKG_SERVER: ${{ matrix.pkg-server }}
 
+      # When using the Pkg server the `Pkg.Registry.add("General")` will add the General registry
+      # via Pkg servers. Using `localregistry` to clone the General registry via HTTPS should be
+      # skipped.
+      - name: Test skipping registry cloning of duplicate repos
+        if: ${{ matrix.pkg-server == 'pkg.julialang.org' }}
+        shell: bash
+        run: |
+          ! test -d $HOME/.julia/registries/General
+
       - uses: julia-actions/julia-runtest@v1
 
       - uses: julia-actions/julia-processcoverage@v1
diff --git a/action.yml b/action.yml
index 2d2d110..8ddd11b 100644
--- a/action.yml
+++ b/action.yml
@@ -41,20 +41,31 @@ runs:
       VERSION >= v"1.7-" && (ENV["JULIA_PKG_USE_CLI_GIT"] = ${{ inputs.git_cli }})
 
       if VERSION < v"1.7-" && ${{ inputs.git_cli }} == true
-        printstyled("::notice::JULIA_PKG_USE_CLI_GIT requires Julia >= 1.7. Using default LibGit2 git-interface instead! \n"; color = :yellow)
+          printstyled("::notice::JULIA_PKG_USE_CLI_GIT requires Julia >= 1.7. Using default LibGit2 git-interface instead! \n"; color = :yellow)
       end
 
-
       if VERSION >= v"1.5-"
-          Pkg.Registry.add("General")
+          function reachable_registries()
+              return if VERSION >= v"1.7-"
+                  Pkg.Registry.reachable_registries()
+              else
+                  [(; name=r.name, repo=r.url) for r in Pkg.Types.collect_registries()]
+              end
+          end
+
+          if !any(r -> r.name == "General", reachable_registries())
+              Pkg.Registry.add("General")
+          end
 
           # If provided add local registries
-          if !isempty("${{ inputs.localregistry }}")
-            local_repos = split("${{ inputs.localregistry }}", "\n") .|> string
-            for repo_url in local_repos
-              isempty(repo_url) && continue
-              Pkg.Registry.add(Pkg.RegistrySpec(; url = repo_url))
-            end
+          if !isempty(ENV["LOCAL_REGISTRY"])
+              local_repos = split(ENV["LOCAL_REGISTRY"], "\n"; keepempty=false) .|> string
+              for repo_url in local_repos
+                  # https://github.com/JuliaLang/Pkg.jl/issues/3753
+                  if !any(r -> r.repo == repo_url, reachable_registries())
+                      Pkg.Registry.add(Pkg.RegistrySpec(; url = repo_url))
+                  end
+              end
           end
       end
 
@@ -63,3 +74,4 @@ runs:
     env:
       JULIA_PKG_PRECOMPILE_AUTO: "${{ inputs.precompile }}"
       GITHUB_TOKEN: ${{ github.token }}
+      LOCAL_REGISTRY: ${{ inputs.localregistry }}