The search now uses an updated jQuery. A change in buffering of the output to stdout during an indexing run reduces the lag time (and just MAY reduce the occurrence of the dreaded 500 error). A fix was developed for the rare case of a “pdf” file being mis-identified in the headers as “text”.
While an upgrade can be done by simply replacing the files noted in the changelog, then running /admin/version_update.php, a clean install is recommended. If you chose just to replace files, it is CRUCIAL that you run version_update.php!