Just went to download Veeam B&R 4.5u4a ISO and the Release Notes link points to Veeam Backup & Replication 9.5.4.2615, which is the old version.
I believe it should say that you need to have installed Veeam B&R 4.5u4 to install the Veeam B&R 4.5u4a patch, otherwise you have to use the full ISO to update. I was hoping to confirm this in the Release Notes...
We commulate release notes for such patches.
Separate release note can be found here: https://www.veeam.com/kb2926
It confirms there that Update 4 is needed.
Regarding the bits. The ISO contains Update 4 and it will automatically update the installation to Update 4a.
Or you can download from the KB just the Update 4a so that you can install it on top of Update 4.
Anyway the setup will warn you if the environment do not have the needed pre requirements.
