I just updated 4 installations with Update 1 and had no problems. One thing I came across was our own VBR server which ran under 9.0.0.773 RTM, Update 1 requires 9.0.0.902 GA... I had to reinstall VBR with the GA release to install the update.
Will 9.0.0.1491 be the final version, or did you came across other bugs which will be implemented in the final Update 1?
Is it possible to already release the changelog? I would like to write an article on my blog about it, and the supporter told me to ask in the forum to get a statement from the product management

Or do I need to become a Veeam Vanguard first


P.S.: there have been no issues during setup, one VBR server needed a restart after installation, he was not able to update the tape server components, but on all installation the patch resolved bug 67278 "standalone drives job sends email notification about waiting tape, however there is an available tape in drive"