Release v3.21.3

.version-determinate

@@ -1 +1 @@
-3.21.2
+3.21.3

doc/manual/source/SUMMARY.md.in

@@ -148,6 +148,7 @@
   - [Contributing](development/contributing.md)
 - [Determinate Nix Release Notes](release-notes-determinate/index.md)
   - [Changes between Nix and Determinate Nix](release-notes-determinate/changes.md)<!-- next -->
+  - [Release 3.21.3 (2026-07-07)](release-notes-determinate/v3.21.3.md)
   - [Release 3.21.2 (2026-06-18)](release-notes-determinate/v3.21.2.md)
   - [Release 3.21.1 (2026-06-08)](release-notes-determinate/v3.21.1.md)
   - [Release 3.21.0 (2026-05-22)](release-notes-determinate/v3.21.0.md)

doc/manual/source/release-notes-determinate/changes.md

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 # Changes between Nix and Determinate Nix
 
-This section lists the differences between upstream Nix 2.34 and Determinate Nix 3.21.2.<!-- differences -->
+This section lists the differences between upstream Nix 2.34 and Determinate Nix 3.21.3.<!-- differences -->
 
 * In Determinate Nix, flakes are stable. You no longer need to enable the `flakes` experimental feature.
 
@@ -210,3 +210,5 @@ This section lists the differences between upstream Nix 2.34 and Determinate Nix
 <!-- Determinate Nix version 3.21.2 -->
 
 * `nix optimise store` is  multi-threaded in Determinate Nix. [DeterminateSystems/nix-src#492](https://github.com/DeterminateSystems/nix-src/pull/492)
+
+<!-- Determinate Nix version 3.21.3 -->

doc/manual/source/release-notes-determinate/v3.21.3.md

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+# Release 3.21.3 (2026-07-07)
+
+* Based on [upstream Nix 2.34.8](../release-notes/rl-2.34.md).
+
+## Binary cache performance improvements
+
+This release includes a number of async rewrites from upstream Nix that make querying missing paths much faster. PR: [DeterminateSystems/nix-src#514](https://github.com/DeterminateSystems/nix-src/pull/514)
+
+## Remote store performance improvements
+
+Registering temporary roots on remote stores (e.g. when doing `nix copy` to a remote store over `ssh-ng`) is now much faster. PR: [DeterminateSystems/nix-src#538](https://github.com/DeterminateSystems/nix-src/pull/538)
+
+Computing closures (e.g. `nix-store -qR`) is now much faster on high-latency `ssh-ng` stores. PR: [DeterminateSystems/nix-src#539](https://github.com/DeterminateSystems/nix-src/pull/539)
+
+## Parallel evaluation performance improvements
+
+This release delivers a number of performance improvements to parallel evaluation.
+
+PRs: [DeterminateSystems/nix-src#531](https://github.com/DeterminateSystems/nix-src/pull/531), [DeterminateSystems/nix-src#535](https://github.com/DeterminateSystems/nix-src/pull/535), [DeterminateSystems/nix-src#536](https://github.com/DeterminateSystems/nix-src/pull/536), [DeterminateSystems/nix-src#537](https://github.com/DeterminateSystems/nix-src/pull/537)
+
+## Miscellaneous improvements
+
+* `nix search` now prints the total number of derivations, in addition to the number of matching derivations. PR: [DeterminateSystems/nix-src#532](https://github.com/DeterminateSystems/nix-src/pull/532)
+
+## Bug fixes and other changes
+
+* Allow local networking in libmicrohttpd and functional tests by @lilyinstarlight in [DeterminateSystems/nix-src#518](https://github.com/DeterminateSystems/nix-src/pull/518)
+* Don't ignore substitution failures for BasicDerivation inputSrcs by @edolstra in [DeterminateSystems/nix-src#520](https://github.com/DeterminateSystems/nix-src/pull/520)
+* Sync with upstream 2.34-maintenance by @edolstra in [DeterminateSystems/nix-src#521](https://github.com/DeterminateSystems/nix-src/pull/521)
+* fixup: make binary cache nuclear option more general by @cole-h in [DeterminateSystems/nix-src#524](https://github.com/DeterminateSystems/nix-src/pull/524)
+* NarInfoDiskCache: Support arbitrary nix-cache-info fields by @edolstra in [DeterminateSystems/nix-src#525](https://github.com/DeterminateSystems/nix-src/pull/525)
+* ci: update DSP on releases by @cole-h in [DeterminateSystems/nix-src#526](https://github.com/DeterminateSystems/nix-src/pull/526)
+* Add some calls to addTempRoot() by @edolstra in [DeterminateSystems/nix-src#527](https://github.com/DeterminateSystems/nix-src/pull/527)
+* flake.lock: Update by @edolstra in [DeterminateSystems/nix-src#529](https://github.com/DeterminateSystems/nix-src/pull/529)
+
+## New Contributors
+* @lilyinstarlight made their first contribution in [DeterminateSystems/nix-src#518](https://github.com/DeterminateSystems/nix-src/pull/518)
+
+**Full Changelog**: [v3.21.2...v3.21.3](https://github.com/DeterminateSystems/nix-src/compare/v3.21.2...v3.21.3)