[openssl-users] OpenSSL 1.1.1 pre-7 or pre-8 connect to 1.1.1 pre-9 oddity?

[Salz, Rich]

    I find it interesting that openssl 1.1.1-pre7 can not connect to a
    server which has openssl 1.1.1-pre9 in place. Nor can Firefox nightly.

This is to be expected.  Pre-9 implements the official RFC version of TLS 1.3, while the earlier beta releases implement drafts.  One of the major differences between the RFC and the drafts, is that (a) they don't interoperate, by design; and (b) fallback is an error.