Lead · May 3, 2026
middleman-s3_sync 4.8.0 released
Immutable caching directives for fingerprinted assets, and max-age finally winning the argument with Expires.
I’ve just released version 4.8.0 of middleman-s3_sync, a gem that synchronizes Middleman-built websites to Amazon S3, with optional CloudFront invalidation. This release tightens the HTTP caching story for hashed assets.
What’s new
immutable directive
Caching policies now support the immutable flag. Pair it with a long max_age on fingerprinted assets — the kind Middleman’s asset_hash extension produces — and browsers will skip revalidation entirely, even on a user-initiated reload:
caching_policy 'text/css', max_age: 1.year, public: true, immutable: true caching_policy 'application/javascript', max_age: 1.year, public: true, immutable: true caching_policy 'image/png',...