Single post in Lag issues, progress, and planned maintenance [TBD]

Yes. The developer(s) will have to fix their stuff. It's also going to break custom site skins, at least a little bit, depending on the complexity of the modifications made. Full details can't be provided at this time. The plan was literally made today, so honestly, asking such questions at such an early stage is only going to yield vague answers, as nothing is underway meaning... You're not really getting a good answer. You're getting a guess!