Yep, in prior years, a few institutions have even turned off their specially-formatted tax import files by the end of July.
Don't know which ones, just a general observation from many years working in this forum.
Thus, to be safe, get all your file imports done by April...even if you eventually file an extension to finish filing at a later date.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
