I'm almost surprised they didn't let the emulator run as-is for another year just to hit the milestone.
Most people will be familiar with the MAME software, which originally stood for Multiple Arcade Machine Emulator. It's been a staple around the internet for almost two decades now, with plenty of people using the program as part of some funky cabinet builds. One Australian used MAME as part of a funky build last year that transformed a wine barrel into a homebrew cabinet.
Thing is, the software hasn't been open source even though it's been widely distributed under the impression that it was.
The team behind MAME has, according to a post on the official website, been spending the better part of a year contacting everyone who contributed to development. "As a result, a great majority of files (over 90% including core files) are available under the 3-Clause BSD License but project as a whole is distributed under the terms of the GNU General Public License, version 2 or later (GPL-2.0+), since it contains code made available under multiple GPL-compatible licenses," the MAME team wrote.
The change won't really affect much for individual users, but it does have an impact on those who might use the software for other projects going forward. "Code that was distributed under the previous MAME license can not be included or linked to MAME from this point forward without being relicensed, requiring permission from all contributors to that code," the team warned in a separate post.