Remove support for CodeQL CLI versions older than 2.21.4

Author: nickrolfe

extensions/ql-vscode/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [UNRELEASED]
 
+- Remove support for CodeQL CLI versions older than 2.21.4. [#4285](https://github.com/github/vscode-codeql/pull/4285)
+
 ## 1.17.7 - 5 December 2025
 
 - Rename command "CodeQL: Trim Overlay Base Cache" to "CodeQL: Trim Cache to Overlay-Base" for consistency with "CodeQL: Warm Overlay-Base Cache for [...]" commands. [#4204](https://github.com/github/vscode-codeql/pull/4204)
@@ -134,6 +136,7 @@
   2. A language selector, which allows you to quickly filter databases and queries by language.
 
   For more information, see the [documentation](https://codeql.github.com/docs/codeql-for-visual-studio-code/analyzing-your-projects/#filtering-databases-and-queries-by-language).
+
 - When adding a CodeQL database, we no longer add the database source folder to the workspace by default (since this caused bugs in single-folder workspaces). [#3047](https://github.com/github/vscode-codeql/pull/3047)
   - You can manually add individual database source folders to the workspace with the "Add Database Source to Workspace" right-click command in the databases view.
   - To restore the old behavior of adding all database source folders by default, set the `codeQL.addingDatabases.addDatabaseSourceToWorkspace` setting to `true`.
@@ -194,7 +197,7 @@ No user facing changes.
 
 - Remove "last updated" information and sorting from variant analysis results view. [#2637](https://github.com/github/vscode-codeql/pull/2637)
 - Links to code on GitHub now include column numbers as well as line numbers. [#2406](https://github.com/github/vscode-codeql/pull/2406)
-- No longer highlight trailing commas for jump to definition.  [#2615](https://github.com/github/vscode-codeql/pull/2615)
+- No longer highlight trailing commas for jump to definition. [#2615](https://github.com/github/vscode-codeql/pull/2615)
 - Fix a bug where the QHelp preview page was not being refreshed after changes to the underlying `.qhelp` file. [#2660](https://github.com/github/vscode-codeql/pull/2660)
 
 ## 1.8.8 - 17 July 2023

extensions/ql-vscode/src/codeql-cli/cli.ts

@@ -45,7 +45,7 @@ import type { LanguageClient } from "vscode-languageclient/node";
  * The oldest version of the CLI that we support. This is used to determine
  * whether to show a warning about the CLI being too old on startup.
  */
-export const OLDEST_SUPPORTED_CLI_VERSION = new SemVer("2.20.7");
+export const OLDEST_SUPPORTED_CLI_VERSION = new SemVer("2.21.4");
 
 /**
  * The version of the SARIF format that we are using.

extensions/ql-vscode/supported_cli_versions.json

@@ -3,6 +3,5 @@
   "v2.23.9",
   "v2.22.4",
   "v2.21.4",
-  "v2.20.7",
   "nightly"
 ]