@@ -24,6 +24,4 @@ When you update your integration to specify the new API version in the `X-GitHub
 
 Once your integration is updated, test your integration to verify that it works with the new API version.
 
-## Breaking changes for {{ initialRestVersioningReleaseDate }}
-
-Version `{{ initialRestVersioningReleaseDate }}` is the first version of the {% data variables.product.github %} REST API after date-based versioning was introduced. This version does not include any breaking changes.
+{% data reusables.rest-api.breaking-changes-changelog %}
@@ -0,0 +1,18 @@
+<!-- markdownlint-disable liquid-quoted-conditional-arg search-replace GHD046 -->
+{% ifversion fpt %}
+{% if query.apiVersion == nil or "2022-11-28" <= query.apiVersion %}
+## Version 2022-11-28
+
+Version `2022-11-28` is the first version of the GitHub Free, Pro & Team REST API after date-based versioning was introduced. This version does not include any breaking changes.
+
+{% endif %}
+{% endif %}
+
+{% ifversion ghec %}
+{% if query.apiVersion == nil or "2022-11-28" <= query.apiVersion %}
+## Version 2022-11-28
+
+Version `2022-11-28` is the first version of the GitHub Enterprise Cloud REST API after date-based versioning was introduced. This version does not include any breaking changes.
+
+{% endif %}
+{% endif %}
@@ -124,28 +124,44 @@ export async function updateAutomatedPipelines() {
     }
 
     // Get a list of data directories to create (release) and create them
-    // This should only happen if a relase is being added.
+    // This should only happen if a release is being added.
     const addFiles = difference(expectedDirectory, existingDataDir)
-    if (addFiles.length > numberedReleaseBaseNames.length) {
-      throw new Error(
-        'Only one new release per numbered release version should be added at a time. Check that the lib/enterprise-server-releases.ts is correct.',
-      )
+
+    // Verify all new directories belong to the current release
+    for (const dir of addFiles) {
+      if (!dir.includes(currentReleaseNumber)) {
+        throw new Error(
+          `Unexpected directory to add: ${dir}. Only directories for the current release ` +
+            `(${currentReleaseNumber}) should be added. Check that the lib/enterprise-server-releases.ts is correct.`,
+        )
+      }
     }
 
     for (const base of numberedReleaseBaseNames) {
-      const dirToAdd = addFiles.find((item) => item.startsWith(base))
-      if (!dirToAdd) continue
-      // The suppported array is ordered from most recent (index 0) to oldest
-      // Index 1 will be the release prior to the most recent release
-      const lastRelease = supported[1]
-      const previousDirName = existingDataDir.filter((directory) => directory.includes(lastRelease))
-
-      console.log(
-        `Copying src/${pipeline}/data/${previousDirName} to src/${pipeline}/data/${dirToAdd}`,
-      )
-      await cp(`src/${pipeline}/data/${previousDirName}`, `src/${pipeline}/data/${dirToAdd}`, {
-        recursive: true,
-      })
+      // Find ALL directories to add for this base name (may be multiple
+      // when a release has more than one calendar-date version).
+      const dirsToAdd = addFiles.filter((item) => item.startsWith(base))
+      for (const dirToAdd of dirsToAdd) {
+        // Derive the previous release's corresponding directory by replacing
+        // the current release number with the previous one. This correctly
+        // maps each calendar-date variant to its predecessor, e.g.:
+        //   ghes-3.20-2022-11-28 → ghes-3.19-2022-11-28
+        //   ghes-3.20-2026-03-10 → ghes-3.19-2026-03-10
+        const previousDirName = dirToAdd.replace(currentReleaseNumber, previousReleaseNumber)
+        if (!existingDataDir.includes(previousDirName)) {
+          throw new Error(
+            `Cannot find previous release directory '${previousDirName}' to copy from ` +
+              `when creating '${dirToAdd}' in src/${pipeline}/data/.`,
+          )
+        }
+
+        console.log(
+          `Copying src/${pipeline}/data/${previousDirName} to src/${pipeline}/data/${dirToAdd}`,
+        )
+        await cp(`src/${pipeline}/data/${previousDirName}`, `src/${pipeline}/data/${dirToAdd}`, {
+          recursive: true,
+        })
+      }
     }
   }
 
 
@@ -21,6 +21,7 @@ import { allVersions } from '@/versions/lib/all-versions'
 import { syncWebhookData } from '../../webhooks/scripts/sync'
 import { syncGitHubAppsData } from '../../github-apps/scripts/sync'
 import { syncRestRedirects } from './utils/get-redirects'
+import { syncChangelogs } from './utils/sync-changelogs'
 import { MODELS_GATEWAY_ROOT, injectModelsSchema } from './utils/inject-models-schema'
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
@@ -130,6 +131,7 @@ async function main() {
   if (pipelines.includes('rest')) {
     console.log(`\n▶️  Generating REST data files...\n`)
     await syncRestData(TEMP_OPENAPI_DIR, restSchemas, sourceRepoDirectory, injectModelsSchema)
+    await syncChangelogs(sourceRepoDirectory, VERSION_NAMES)
   }
 
   if (pipelines.includes('webhooks')) {
 
@@ -0,0 +1,190 @@
+import { readFile, writeFile } from 'fs/promises'
+import { existsSync } from 'fs'
+import path from 'path'
+
+import { allVersions } from '@/versions/lib/all-versions'
+
+const REST_API_DESCRIPTION_ROOT = 'rest-api-description'
+const OUTPUT_PATH = 'data/reusables/rest-api/breaking-changes-changelog.md'
+
+interface VersionMapping {
+  sourceDir: string
+  ifversionExpr: string
+}
+
+interface VersionSection {
+  version: string
+  content: string
+}
+
+// Build a list of { sourceDir, ifversionExpr } tuples from allVersions.
+// For example:
+//   fpt → source dir "api.github.com", ifversion "fpt"
+//   ghec → source dir "ghec", ifversion "ghec"
+//   ghes-3.14 → source dir "ghes-3.14", ifversion "ghes = 3.14"
+function buildVersionMappings(versionNames: Record<string, string>): VersionMapping[] {
+  // Build reverse lookup: docs short name → source directory name
+  // e.g. "fpt" → "api.github.com", "ghec" → "ghec"
+  const reverseMapping: Record<string, string> = {}
+  for (const [sourceDir, docsName] of Object.entries(versionNames)) {
+    reverseMapping[docsName] = sourceDir
+  }
+
+  const mappings: VersionMapping[] = []
+  const seen = new Set<string>()
+
+  for (const versionObj of Object.values(allVersions)) {
+    const key = versionObj.openApiVersionName
+    if (seen.has(key)) continue
+    seen.add(key)
+
+    let sourceDir: string
+    let ifversionExpr: string
+
+    if (versionObj.shortName === 'ghes') {
+      // GHES versions: source dir is like "ghes-3.14", ifversion is "ghes = 3.14"
+      sourceDir = `ghes-${versionObj.currentRelease}`
+      ifversionExpr = `ghes = ${versionObj.currentRelease}`
+    } else {
+      // Non-GHES: look up source dir from reverse mapping
+      sourceDir = reverseMapping[versionObj.shortName] || versionObj.shortName
+      ifversionExpr = versionObj.shortName
+    }
+
+    mappings.push({ sourceDir, ifversionExpr })
+  }
+
+  return mappings
+}
+
+// Resolve the changelog file path based on whether we're using
+// rest-api-description or the local github repo.
+export function getChangelogPath(sourceRepoDir: string, releaseDir: string): string {
+  if (sourceRepoDir === REST_API_DESCRIPTION_ROOT) {
+    return path.join(REST_API_DESCRIPTION_ROOT, 'descriptions-next', releaseDir, 'CHANGELOG.md')
+  }
+  // Local github repo dev workflow
+  return path.join(
+    sourceRepoDir,
+    'app',
+    'api',
+    'description',
+    'changelogs',
+    releaseDir,
+    'CHANGELOG.md',
+  )
+}
+
+// Parse a CHANGELOG.md into an array of { version, content } objects
+// by splitting on `## Version YYYY-MM-DD` headings.
+// Strips the top-level `# REST API Breaking Changes for ...` title and intro paragraph.
+export function parseVersionSections(markdown: string): VersionSection[] {
+  const lines = markdown.split('\n')
+  const sections: VersionSection[] = []
+  let currentVersion: string | null = null
+  let currentLines: string[] = []
+  let pastHeader = false
+
+  for (const line of lines) {
+    // Skip the top-level title (# REST API Breaking Changes ...)
+    if (!pastHeader && line.startsWith('# ')) {
+      pastHeader = true
+      continue
+    }
+
+    // Skip intro paragraph lines before the first ## Version heading
+    const versionMatch = line.match(/^## Version (\d{4}-\d{2}-\d{2})/)
+    if (versionMatch) {
+      // Save previous section if any
+      if (currentVersion) {
+        sections.push({
+          version: currentVersion,
+          content: currentLines.join('\n').trim(),
+        })
+      }
+      currentVersion = versionMatch[1]
+      currentLines = [line]
+      pastHeader = true
+      continue
+    }
+
+    if (currentVersion) {
+      currentLines.push(line)
+    }
+  }
+
+  // Save last section
+  if (currentVersion) {
+    sections.push({
+      version: currentVersion,
+      content: currentLines.join('\n').trim(),
+    })
+  }
+
+  return sections
+}
+
+// Main function: reads changelogs from each release directory, wraps them
+// in product-version gating ({% ifversion %}) and API-version filtering
+// ({% if query.apiVersion %}), and writes a combined data file.
+export async function syncChangelogs(
+  sourceRepoDir: string,
+  versionNames: Record<string, string>,
+  outputPath: string = OUTPUT_PATH,
+): Promise<void> {
+  console.log(`\n▶️  Generating REST API breaking changes changelog...\n`)
+
+  const mappings = buildVersionMappings(versionNames)
+  const outputBlocks: string[] = []
+
+  for (const { sourceDir, ifversionExpr } of mappings) {
+    const changelogPath = getChangelogPath(sourceRepoDir, sourceDir)
+
+    if (!existsSync(changelogPath)) {
+      console.log(`  ⏭️  No changelog found for ${sourceDir}, skipping.`)
+      continue
+    }
+
+    const markdown = await readFile(changelogPath, 'utf-8')
+    const sections = parseVersionSections(markdown)
+
+    if (sections.length === 0) {
+      console.log(`  ⏭️  No version sections found in changelog for ${sourceDir}, skipping.`)
+      continue
+    }
+
+    const sectionBlocks = sections.map(({ version, content }) => {
+      return [
+        `{% if query.apiVersion == nil or "${version}" <= query.apiVersion %}`,
+        content,
+        '',
+        '{% endif %}',
+      ].join('\n')
+    })
+
+    const releaseBlock = [
+      `{% ifversion ${ifversionExpr} %}`,
+      sectionBlocks.join('\n'),
+      '{% endif %}',
+    ].join('\n')
+
+    outputBlocks.push(releaseBlock)
+    console.log(`  ✅ Processed changelog for ${sourceDir} (${sections.length} version sections)`)
+  }
+
+  if (outputBlocks.length === 0) {
+    console.log('  ⚠️  No changelogs found. Skipping changelog generation.')
+    return
+  }
+
+  // The generated Liquid uses quoted date strings in comparisons
+  // (e.g., "2022-11-28" <= query.apiVersion) which is valid Liquid but
+  // triggers the GHD016 lint rule that flags quoted conditional args.
+  // The upstream changelogs may also contain docs.github.com URLs and
+  // "deprecated" terminology that trigger docs-domain and GHD046 rules.
+  const lintDisable =
+    '<!-- markdownlint-disable liquid-quoted-conditional-arg search-replace GHD046 -->\n'
+  const output = `${lintDisable + outputBlocks.join('\n\n')}\n`
+  await writeFile(outputPath, output)
+  console.log(`\n✅ Wrote ${outputPath}`)
+}