# Version 89.0 "And the Melody Still Lingers On (Night in Tunisia)" 2024-12-27
## New features and enhancements
* mkvmerge: AC-3 writer: mkvmerge will now use the codec ID `A_AC3` even for
streams with bitstream IDs 9 or 10 instead of the deprecated codec IDs
`A_AC3/BSID9` & `A_AC3/BSID10`. Fixes #2387.
* MKVToolNix GUI: multiplexer: the mechanism for setting track languages to
specific values upon adding a file has gotten a new option to always set the
language, no matter whether or not the source container provided a track
language or what it was set to.
* all command-line tools: implemented an escape mechanism for when you want to
use the `@` sign as the first character in an argument to an option such as
`--title`. To escape it the `@` sign has to be doubled as in `--title
@@midnight`. Implements #3768.
## Bug fixes
* mkvmerge, mkvpropedit, MKVToolNix GUI's multiplexer & header editor: the
MIME type for TrueType & OpenType fonts will be set properly to either the
current MIME types `font/ttf` & `font/otf` or to the legacy MIME types
`application/x-truetype-font` & `application/vnd.ms-opentype` depending on
whether the "use legacy font MIME types" option is disabled or enabled, even
if the MIME database used by Qt returns the wrong one or even other MIME
types such as `application/x-font-ttf` & `application/x-font-otf`. This was
the case on Windows due to Qt 6.7.3 switching to a different embedded MIME
database. Partially fixes #3751.
* MKVToolNix GUI's multiplexer & header editor: ensured that both the legacy &
the current font MIME types are always present in the MIME type combo boxes
of attachments, no matter what Qt's MIME type database contains. Partially
fixes #3751.
* MKVToolNix GUI: the "disable tooltips" option in the preference will now
disable the tooltip for the status bar, too.