Threading was broken if information was needed from References header.
For example, mailman might alter some Message-IDs when using its NNTP
bridge and the complete references are necessary to rebuild the thread,
which is only available in References whereas ENVELOPE has only
In-Reply-To.
Add support for header caching. It is currently unstable and should not
be used. It can be turned on by specifying "X_header_caching" to true in
the IMAP account's configuration.
The header cache is saved in a sqlite3 database in your XDG_DATA_DIR,
for example:
/home/epilys/.local/share/meli/17328072387188469646_header_cache.db
Concerns #31https://git.meli.delivery/meli/meli/issues/31
Manos Pitsidianakis