Hmm yeah. Upgraded mine to 2.5.1 and still unable to get synced up. What server are you connecting to? I think some servers are not up to date yet. Either way I have a couple of wallets in Electrum and not one is syncing up.
Also not a big fan of the wallet firing up a new instance now (2nd wallet) if you want to switch between wallets. Eats up extra ram which is unnecessary. I like the previous approach of the Electrum shutting the current wallet down to load a different one more convenient.
Anyway, big Electrum fan just would be nice if I could get at least one of my wallets synced