5.2.3

• Improved caching the count

5.2.2

• Fixed performance issues for count operations

BSON ended up re-indexing documents when the count was being read

• Fixed BSONEncoder refusing the max and min value for an integer

5.2.1

• Fixed a very obscure bug that would sometimes cause misinterpreting "primitive" BSON values (like Double, Int) when the backing storage of the array containing the bytes of the Document is not contiguous
• Added a range check in the Int initializer, to prevent crashes when converting a Double whose value falls outside the Int.min-Int.max range

5.2.0

Swift 4 codable support. Swift 3.0 and 3.1 are still supported, too, but without Codable.

5.1.5

• Fixed the internal cache not updating properly on append

5.1.4

• Fixed index mutations affecting other documents

4.1.5

Fixed a very specific ExtendedJSON serialization bug

5.1.3

• Better subdocument equation

5.1.2

Fixed creation of documents from an arrayslice with an offset of startIndex > 0

5.1.1

• Fixed DictionaryValue, it's been broken for months apparently.
• Fixed overall correctness in validation (too permissive)
• Fixed array validation (not permissive enough, arrays with the key "username" make sense apparently)
• Complete unit test suite for BSON's Spec