>=net-p2p/syncthing-1.17.0 incompatibility warning - 18/05/2021 00:00 GMT

Starting with version 1.17.0, net-p2p/syncthing by default only allows
TLS 1.3 for sync connections - making it impossible to sync with devices
not supporting it, i.e. running Syncthing versions older than 1.3.0.

If you do require your Syncthing cluster to support TLS 1.2, you will have to
explicitly allow it by enabling the option "insecureAllowOldTLSVersions".
For details see:

https://docs.syncthing.net/advanced/option-insecure-allow-old-tls-versions.html