Support for metadata lookup changes is added. User configuration required.
Details at: https://www.mythtv.org/wiki/Metadata_Lookup_Changes_March_2021

Support for Python 2.7 is removed.

If a MYSQL server is installed, a mythtv MySQL user and mythconverg database
is created if it does not already exist.
You will be prompted for your MySQL root password.

A mythtv user is maintained by acct-user/mythtv. An existing mythtv user
may be modified to the configuration defined by acct-user/mythtv.
The mythtv user's primary group is now mythtv. (formerly video)
An existing mythtv user may be changed which may alter some functionality.
If it breaks mythtv you may need to (choose one):
        * Restore the original mythtv user
        * Create custom acct-user/mythtv overlay for your system
        * Fix you system to use mythtv as daemon only (recommended)
Failure to emerge acct-user/mythtv indicates that the existing mythtv user
is customized and not changed. Corrective action (choose one):
        * Ignore emerge failure
        * Create custom acct-user/mythtv overlay for your system
        * Fix you system to use mythtv as daemon only
        * Delete existing user and try again (dangerous)

Mythtv is updated to use correct FHS/Gentoo policy paths.
Updating mythtv installations may report:
        * mythtv is in use, cannot update home
        * There was an error when attempting to update the home directory for mythtv
        * Please update it manually on your system (as root):
        *       usermod -d "/var/lib/mythtv" "mythtv"
This can be ignored. The previous default was "/home/mythtv".
Use caution if you change the home directory.

To have this machine operate as recording host for MythTV,
mythbackend must be running. Run the following:
rc-update add mythbackend default

Your recordings folder must be owned 'mythtv'. e.g.
chown -R mythtv /var/lib/mythtv

Want mythfrontend to start automatically?
Set USE=autostart. Details can be found at:
https://dev.gentoo.org/~cardoe/mythtv/autostart.html