Mark Core 1 as unsupported, clarify browser support (#2190)

Author: dstaley

docs/upgrade-guides/long-term-support.mdx

@@ -15,7 +15,7 @@ After the LTS period ends, there will be no further changes to the code for that
 | Version | Status | As Of | Until |
 | - | - | - | - |
 | Core 2 | Active | April 19, 2024 | TBD |
-| Core 1 | Long term support | April 19, 2024 | Q1 2025 |
+| Core 1 | Unsupported | - | - |
 | Legacy (v3) | Unsupported | - | - |
 
 ## Library compatibility
@@ -24,8 +24,8 @@ Clerk's SDKs run in the browser, in Node.js (+ other compatible runtimes), or in
 
 | Version | Node.js | Browsers |
 | - | - | - |
-| Core 2 | `>=18.17.0` | Evergreen, iOS 16 |
-| Core 1 | `>=14.0.0` | Evergreen, iOS 16 |
+| Core 2 | `>=18.17.0` | Browsers released in the last two years |
+| Core 1 | `>=14.0.0` | Chrome 114, Edge 115, Firefox 116, Safari 12.1 |
 
 ## Terminology