diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5d74860923..add4d518ed 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ Note that the only difference between `v2` and `v3` of the CodeQL Action is the
 ## [UNRELEASED]
 
 - Add `codeql-version` to outputs. [#2368](https://github.com/github/codeql-action/pull/2368)
+- Add a deprecation warning for customers using CodeQL version 2.13.4 and earlier. These versions of CodeQL were discontinued on 9 July 2024 alongside GitHub Enterprise Server 3.9, and will be unsupported by CodeQL Action versions 3.26.0 and later and versions 2.26.0 and later. [#2375](https://github.com/github/codeql-action/pull/2375)
+  - If you are using one of these versions, please update to CodeQL CLI version 2.13.5 or later. For instance, if you have specified a custom version of the CLI using the 'tools' input to the 'init' Action, you can remove this input to use the default version.
+  - Alternatively, if you want to continue using a version of the CodeQL CLI between 2.12.6 and 2.13.4, you can replace `github/codeql-action/*@v3` by `github/codeql-action/*@v3.25.13` and `github/codeql-action/*@v2` by `github/codeql-action/*@v2.25.13` in your code scanning workflow to ensure you continue using this version of the CodeQL Action.
 
 ## 3.25.12 - 12 Jul 2024
 
diff --git a/lib/api-compatibility.json b/lib/api-compatibility.json
index 3b089e3e2d..65b505c94e 100644
--- a/lib/api-compatibility.json
+++ b/lib/api-compatibility.json
@@ -1 +1 @@
-{ "maximumVersion": "3.14", "minimumVersion": "3.9" }
+{ "maximumVersion": "3.14", "minimumVersion": "3.10" }
diff --git a/lib/codeql.js b/lib/codeql.js
index a8cb513926..fcf4dd54da 100644
--- a/lib/codeql.js
+++ b/lib/codeql.js
@@ -66,15 +66,15 @@ const CODEQL_MINIMUM_VERSION = "2.12.6";
 /**
  * This version will shortly become the oldest version of CodeQL that the Action will run with.
  */
-const CODEQL_NEXT_MINIMUM_VERSION = "2.12.6";
+const CODEQL_NEXT_MINIMUM_VERSION = "2.13.5";
 /**
  * This is the version of GHES that was most recently deprecated.
  */
-const GHES_VERSION_MOST_RECENTLY_DEPRECATED = "3.8";
+const GHES_VERSION_MOST_RECENTLY_DEPRECATED = "3.9";
 /**
  * This is the deprecation date for the version of GHES that was most recently deprecated.
  */
-const GHES_MOST_RECENT_DEPRECATION_DATE = "2024-03-26";
+const GHES_MOST_RECENT_DEPRECATION_DATE = "2024-07-09";
 /** The CLI verbosity level to use for extraction in debug mode. */
 const EXTRACTION_DEBUG_MODE_VERBOSITY = "progress++";
 /*
diff --git a/src/api-compatibility.json b/src/api-compatibility.json
index 6824bcb794..d7bd9c14ae 100644
--- a/src/api-compatibility.json
+++ b/src/api-compatibility.json
@@ -1 +1 @@
-{"maximumVersion": "3.14", "minimumVersion": "3.9"}
+{"maximumVersion": "3.14", "minimumVersion": "3.10"}
diff --git a/src/codeql.ts b/src/codeql.ts
index e4cac65c22..ebc02e1eff 100644
--- a/src/codeql.ts
+++ b/src/codeql.ts
@@ -281,17 +281,17 @@ const CODEQL_MINIMUM_VERSION = "2.12.6";
 /**
  * This version will shortly become the oldest version of CodeQL that the Action will run with.
  */
-const CODEQL_NEXT_MINIMUM_VERSION = "2.12.6";
+const CODEQL_NEXT_MINIMUM_VERSION = "2.13.5";
 
 /**
  * This is the version of GHES that was most recently deprecated.
  */
-const GHES_VERSION_MOST_RECENTLY_DEPRECATED = "3.8";
+const GHES_VERSION_MOST_RECENTLY_DEPRECATED = "3.9";
 
 /**
  * This is the deprecation date for the version of GHES that was most recently deprecated.
  */
-const GHES_MOST_RECENT_DEPRECATION_DATE = "2024-03-26";
+const GHES_MOST_RECENT_DEPRECATION_DATE = "2024-07-09";
 
 /** The CLI verbosity level to use for extraction in debug mode. */
 const EXTRACTION_DEBUG_MODE_VERBOSITY = "progress++";