Hi! "Downgrading is possible to v2.2.27 and later. (v2.2.27 accidentally broke dovecot.index* backwards compatibility a bit.) "
I've thrown caution to the winds, and downgraded back to 2.2.22, by turning off the Dovecot-PPA, deinstalling 2.3.0.1, and installing 2.2.22 again from the Ubuntu package sources. Then I could at least log in to the dovecot server again. But i still needed Pigeonhole 0.4.14, and in 2.2.22 there is only 0.4.13. "IMAP Sieve" is not added before 0.4.14. I have a Kubuntu 16.04.3 LTS System, and the contained version is only 2.2.22. So I downloaded and installed the needed dovecot packages from the newer Ubuntu version 17.10. That's version 2.2.27. And now - I can log in, and there are no complaints about the IMAPSieve-configuration not being recognized. (I need IMAPSieve for the training of a spam filter). Now I can continue with that spam filter. So far, I habe no problems with the broken indexes - yet(??) (see above). Eventually it can be said that the problem is probably an incompatibility between the dovecot wich ich packaged for Ubuntu, and the version from the dovecot PPA. Tschüß Volker
