I rolled Mediawiki on Sonic Retro from 1.16 back to 1.15 because it fundamentally breaks some tools we have. This shouldn't be a real issue aside from the fact that MW 1.16 stores preferences differently than 1.15 does; as a result, you may find your skin choice, thumbnail sizes, etc., gone. Just go to Special:Preferences and re-set them. This also may make Recent Changes disappear; just reclick your preferred dayspan/number of edits you like to see. Thanks.