Great. The updater shipped with oC 9.1.1 might be not showing this issue so it could be possible that you can use the updater onwards without doing that steps.
Just some additional info. It seems that the "beta" channel is actually even providing 9.1.0 RC1 where it is claiming that 9.1.0 is shipped. In between there where also RC2, RC3 and RC4.
Hi All, Although this issue has been fixed by manual update, I would like to share the solution where you can run the update from web gui for anyone that is searching around in this error just like me. The reason we get "Failed to connect to xxx.xxx.xxx.xxx port 443: Connection timed out" is due to no connection from public to your owncloud server from owncloud server itself. Let me explain more. Normally, owncloud server is hosted in DMZ or your LAN and you NAT 443 traffic from your firewall to your OC server. Therefore OC server cannot access itself from NAT public IP. Solution is that change DNS server on your OC server or create alias so that when you ping your OC DNS, it should resolve local IP rather than public IP. Once you doing that, web gui update could run without curl error. Change DNS server or remove alias once upgrade is done. I just did on my server and want to share to everyone.