# Whiley v0.3.37 Released!

Another big update to Whiley landed today, and includes a whole raft of changes. In particular, various algorithms in the automated theorem prover have been reworked to improve performance (though more still needs to be done here). A rough summary of the changes in this version is:

**Performance Improvements for Automated Theorem Prover**. In particular, the automated theorem prover is updated to the latest version of WyRL (v0.4.3). The main improvements are: 1) the rewrite history is now managed through a single`Automaton`

(#17,#18); 2) an incremental algorithm for implementing efficient`rewrite()`

is included, though it is not yet properly incremental (#19,#28).**Updates to Theorem Prover Rewrite Rules**. In particular, for the new`requires`

clause which is now supported by WyRL (#548).**Improved to Standard Library Specifications**. Various methods in the standard library (`replace()`

,`slice()`

,`append()`

,`indexOf()`

,`lastIndexOf()`

) have had their specifications updated to be more complete. The work to fully specify all parts of the standard library is ongoing, however (#530).

At this point, the next major improvements I plan to work on are to get type invariants working properly again (#538,#528,#469,#468), and to continue refactoring the compiler ( e.g. #502,#501,#474). That should keep me busy enough for a while!