See also http://pvp.haskell.org/faq

1.2.1.0

Bugfix for GHC 9.0.1 memory corruption bug (#46)
- Thanks to Fraser Tweedale and Andrew Lelechenko for logging and helping with this fix.

1.2.0.1

Package update: support for bytestring >=0.11

1.2.0.0

Security fix: reject non-canonical base64 encoded values - (#38) fixing issue #24.
Security fix: reject bytestrings with improper padding that can be "completed" by the unpadded-Base64url workflow, and homogenize error messages (#33)
Test coverage expanded to 98% of the library. All critical paths covered.

1.1.0.0

joinWith has been removed (#32)
Bugfix: decode formerly allowed for padding chars to be interspersed in a valid base64-encoded string. This is now not the case, and it is fully spec-compliant as of #31
The default behavior for Base64url decode is now to support arbitrary padding. If you need strict padded or unpadded decode semantics, use decodePadded or decodeUnpadded.
Added strict unpadded and padded decode functions for Base64url (#30)
Added unpadded encode for Base64url (#26).

1.0.0.3

Made performance more robust (#27).
Improved documentation (#23).
Improved the performance of decodeLenient a bit (#21).

1.0.0.2

Fixed a write past allocated memory in joinWith (potential security issue).

0.1.1.0 - 1.0.0.1

Changelog not recorded for these versions.

0.1.0.3

Fixed: wrong encoding table on big-endian systems.
Fixed: too big indices in encoding table construction.

0.1.0.2

Changelog not recorded up to this version.