Yeah, why would a house built before 1930 - 1977 need any updates during that period, seems sus?

Do note, because it’s using email, the recipient and sender are not private, along with the time, and probably the relative size of the messages.

The specific content of each message should be private as long as the encryption is done well. I haven’t looked at it so I don’t know if it implemnts safeguards to verify who you’re messaging with (besides using the email address) and I don’t know if it uses PFS (Perfect Forward Secrecy) to protect against a key getting compromised.