Do I need to update Apple Mail for BT Mail's new TLS layer?

I found this on the BT site with detailed instructions for setting up Apple Mail on iPhone, iPad, or macOS:

https://www.bt.com/help/email/email-security/securing-your-email-client

Here's what I found in Apple Support:

TLS security - Apple Support

TLS itself has been at version 1.3 since 2018, so this is probably your mail provider either dropping cleartext access, and maybe they’re dropping some very old TLS, or both.

Anything running iOS 26 is capable of access, and usually defaults to secure access.

In the unlikely case the connection is not already secure, removing and re-adding the account should suffice.