2010/12/31 Radim Kolar <hsn(a)sendmail.cz>cz>: There are no big stability problems with either 1.17 (/branches/REL1_17 , which you don't seem to be running because none of the BaseTemplate code is in there) or trunk (/trunk/phase3). The error you're running into is just someone making a silly mistake (not putting the BaseTemplate class in the AutoLoader) and should already be fixed, from looking at the code. This kind of thing happens in development code every now and then, and it hardly ever takes more than a few hours to be noticed and fixed (usually much faster, even). As for 1.17 vs. trunk: your DB2 development work should be done in /trunk/phase3 , that's where all development happens. At this point 1.17 is sort of being frozen, so only bugfixes and the like are merged from trunk to the 1.17 branch. This means your DB2 work won't be part of 1.17 (not will any other new features), but it'll be in 1.18 if it's sufficiently stable by then. No worries, you're in the right place. MediaWiki developers also hang out on IRC (#mediawiki on freenode), you're welcome there for getting advice from fellow developers and telling them the next time trunk breaks like that :) Roan Kattouw (Catrope)