I wrote a blog post describing some of the highlights in greater detail

The type analysis currently keeps track of the types of all elements in tuples and will omit unnecessary type tests for known elements. (That also cover Erlang records, since they are tuples.)

Currently, the type analysis pass does not keep track of the keys or values for maps. It only keeps tracks of variables that are maps, so that the is_map test can be omitted, but there will be repeated tests for __struct__.

We plan to improve the type analysis pass in OTP 23 and it is very likely that it will be extended to keep track of keys and values in maps.

This is the biggest thing that jumped out at me:

           OTP-14894    Application(s): compiler
           Related Id(s): ERL-714

           The compiler has been rewritten to internally use an
           intermediate representation based on Static Single
           Assignment (SSA). The new intermediate representation
           makes more optimizations possible.

           Most noticeable is that the binary matching
           optimizations are now applicable in many more
           circumstances than before.

           Another noticeable change is that type optimizations
           are now applied across local function calls, and will
           remove a lot more redundant type tests than before.