Update changelogs from fern repo (#5263)

Co-authored-by: dsinghvi <10870189+dsinghvi@users.noreply.github.com>

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2026-04-30.mdx

@@ -1,3 +1,11 @@
+## 5.2.0
+**`(feat):`** Add `multi-source` property to docs.yml `instances` configuration. When enabled, docs registration
+uses a basepath-aware S3 key format, allowing multiple independent doc sites to be hosted under the
+same custom domain with different basepaths. This replaces `experimental.basepath-aware`, which is now
+deprecated but still supported. When `multi-source: true`, the CLI validates that the `url` and
+`custom-domain` share the same basepath.
+
+
 ## 5.1.0
 **`(internal):`** Introduce a simpler TtyAwareLogger local to `cli-v2`. The new logger drops
 legacy behaviours that cli-v2 did not use (`omitOnTTY`, `FERN_SPINNER_STATUS`,

fern/products/sdks/generators/csharp/changelog/2026-04-30.mdx

@@ -1,3 +1,10 @@
+## 2.64.0
+**`(feat):`** Add `retryStatusCodes` config with `"legacy"` and `"recommended"` modes. Legacy (default)
+preserves current behavior (408, 429, >= 500). Recommended retries only transient
+codes (408, 429, 502, 503, 504), avoiding idempotency issues with 500. A 3.0.0
+migration auto-pins legacy for upgrading users.
+
+
 ## 2.63.3
 **`(fix):`** Fix dynamic snippets emitting wrong property name when PascalCase(property)
 collides with class name (e.g. CatalogV1Id.catalog_v1_id). The snippet

fern/products/sdks/generators/typescript/changelog/2026-04-30.mdx

@@ -0,0 +1,7 @@
+## 3.67.0
+**`(feat):`** Add `retryStatusCodes` generator config option with `legacy` and `recommended` modes.
+`legacy` (default) preserves current behavior (retries 408, 429, and all 5xx).
+`recommended` retries only 408, 429, 502, 503, and 504, avoiding idempotency
+issues with non-transient server errors like 500.
+
+