Little OT, but not so much 😀
To manage your sieve scripts from Thunderbird 115 there's this nightly build, until developer will code a proper release with fixes.
You can read the issue at https://github.com/thsmi/sieve/issues/893 and I've uploaded the file for convenience here.
My server comes with a default sieve to filter spam messages and another one to move Delta Chat emails:
require ["fileinto"];
# rule:[DeltaChat]
if header :contains "Chat-Version" "1.0"
{
fileinto "DeltaChat";
stop;
}
# rule:[SPAM Check]
if header :contains "X-Spam-Flag" "YES"
{
fileinto "Junk";
stop;
}