As of this week, websites hosted on PythonAnywhere using HTTPS will only be accessible using modern versions of TLS (the encryption protocol on which HTTPS is based) by default. This will make them all more secure.
We can still support older versions of TLS for custom domains if you need to support them, but you’ll need to get in touch with us to get it set up.
We’ve written a help page with the background – please let us know in the comments if there’s anything confusing there!