Hello,
I just wanted to share two notes on Redmine:
(1) When replying to a ticket via e-mail, please ensure to use the e-mail address associated with your account. Otherwise, to prevent spam, messages will be silently discarded.
(2) Note that ONLY the ticketing is supported officially for the individual projects. Please do NOT enable other features (discussions, files, wiki etc.) without talking to the infra team. For those projects already having them enabled, we won't disable them, but I'd like to provision for the future. 
Rationale is that we don't want to end up with five wikis and seven forums per project, spread across a dozen of tools.
Besides that - happy to answer questions on Redmine, ideally personally on FOSDEM.
Florian