Exactly. I was running a much older version of WP and it took 6 hours to upgrade, including making sure all the plugins worked correctly. I immediately got the

Exactly. I was running a much older version of WP and it took 6 hours to upgrade, including making sure all the plugins worked correctly. I immediately got the "white screen of death" afterwards and had to do a binary search to figure out which plugin(s) were the culprit (and then try to track down newer versions or alternatives). Some API changes are not backwards-compatible, so your themes have to be upgraded also (for example, the "show comments" api will by default say "comments off" on every page that doesn't allow them, which it didn't before). I'm sure there's other such changes I haven't yet noticed. I'm glad I upgraded, but it was a major hassle and nearly a full day's work in my case.