It's been due for a while now but we had to go through several server upgrades to be able to add any new content. Finally, I am happy to announce that we now have MAME upgrade packs for people who are still on MAME 0.155. You can find the 0.155 to 0.156, 0.156 to 0.157, and the new 0.157 to 0.158 MAME upgrade packs at this page: Complete ROM Sets Section - Sets beginning with M

For those of you who are just starting out with MAME, you can grab the MAME 0.151 full set and then proceed to upgrade your sets using our upgrade packs, all the way to 0.158. That way you can have a complete and current set of MAME ROMs.