Unlikely this is based on the PMS upgrade.
Did you already have a look at the related troubleshooting support article?
https://support.plex.tv/articles/200931138-troubleshooting-remote-access/
There’s also a guide with some more details on how to troubleshoot remote access issues.
I recommend you start by verifying your remote setup is properly working and visible from outside your home network (e.g. using a service like canyouseeme.org). While testing this, you should also verify if the public IP seen by that site matches that of your router’s WAN IP and the public IP listed in Plex‘s remote access settings.
https://forums.plex.tv/t/the-basics-of-remote-access-troubleshooting/769517
