use of engines in correspondence games

I've heard that in traditional correspondence chess the use of engines is legal nowadays. But what about Lichess-correspondence games? I ask because I'm not sure if it makes sense to report a suspected cheater.

Opening book and analysis board (no engine) is what I remember reading from last time. I'm sure I'll be set right soon if I'm incorrect.

EDIT:
On Lichess, the main difference in rules for correspondence chess is that an opening book is allowed. The use of engines is still prohibited and will result in being flagged for engine assistance. Although ICCF allows engine use in correspondence, Lichess does not.

lichess.org/faq#correspondence

The rule here is no engines, but it's very hard to enforce. The problem is that a good correspondence player will have a lot of deep opening analysis made before a game starts with engine analysis.

I don't know who t f would want to play with someone who uses an engine...

As far as I know the ICCF allows engine use because it has no way to enforce them not being used...In my mind using engine assistance in correspondence chess is madness, I mean why bother playing at all. But human nature being what it is, the ICCF threw their hands up in the air and said, 'we give up, use it if you want to'...

Technology has been a mixed blessing. On one hand it has allowed players throughout the world to play chess with anyone, anywhere at any time which is great...but on the other hand the use of chess engines while actually playing the game is...well it just isn't chess anymore, it's a rigged game....but I guess that's life, everything seems to be a trade-off...

Human Correspondence Chess is dead. It's engine vs. engine today.

Engine use is not allowed in Lichess correspondence, but there seems to be zero enforcement. I've reported players who blatantly use Stockfish's top choice for almost every move and nothing was done.

My experience here so far has been pretty good. Hardly any suspicions have been raised...

I play nothing but correspondence chess both here and at another site and I would have to agree with MrPushwood in that I have no complaints...I don't think anyone has ever used an engine while playing me (as far as I can tell).

There are honest players out there (a lot of them) who just want to engage and enjoy in the struggle of competition that is chess.

Every chess game is a story...Sometimes Greek tragedy and sometimes in my case Greek comedy...

This isn't ICCF and engines are not allowed in any type of games, well, unless you are playing on a BOT account - see lichess.org/api#tag/Bot
As for analysis board in correspondence games, please use the one available in game, unless you want to get flagged. See lichess.org/forum/lichess-feedback/correspondence-game-cheet-detected?page=2#15