Freeswitch 1.10.9 TLS 1.3 only on Debian 11

I have a few Debian 9 servers with Fusionpbx and Freeswitch 1.10.6. I want to migrate these to a newer server.

So I installed latest fusionpbx and 1.10.9 on a Debian 11 server and moved over the data. All is well except for one issue.

I cannot get any handset to register using TLS on port 5061 as it requires TLS1.2. If I run an SSL checker the only protocol that is available is TLS1.3.

I checked and changed the following:

  1. openssl: minprotocol=TLSv1.2
  2. openssl: CipherString = Default@Sec:evel=2
  3. vars.xml: internal profile: sip_tls_version: TLS 1.2, TLS1.1, TLS1

I know that TLS1.2 is available as I’ve configured nginx to use this version and I’m able to connect.

Not sure where else to look. Any help greatly appreciated.