New stable / bugfix release: - create mu cache path if needed - fix empty 'To:' header on reply to icalendar invitation - use const char* from for time_to_string (avoids crash in some configs) - mu4e-headers: appease byte-compiler - mu4e-headers: fallback to :subject for :thread-subject - mu-query-match-decider: add 'Related' to flags (rather than replace)