Lantern as of 6.26 now supports Playing Correspondence with a new tab on the Activities window for it. Games are shown there with options to examine, spositions or make moves after double clcking on a game. 6.26 also shows correspondence notifications if a move is made while the user is online with a sound that can be turned off in Options / Sounds.
Many users play correspondence chess on chessclub's mobile apps, Chess at ICC on Android and iOS, and want support in a chessclub.com desktop app. I've recently found out that Lantern Chess on ICC has support for command line commands and some Interface support working as well. Below I've outlined how to play with Lantern. Games should still be started on the mobile apps.
To List the users correspondence games, type in the M0 tab, /cc-list
A game listing can look like
White Black Last-Move-Time Turn Comment
#1823704676 rookers (1600) *Mike (1600) 2022-06-07 22:59:18 e5 Nf3
Type in this case, same place, M0, /examine #1823704676 and this will open the game in an examine board to view.
To move, using the game number in cc-list, type /cc-move #1823704676 a3, and a board tab will open showing the candidate move.
The moves must be typed in standard notation, but once typed the interface will open the position on a new board to take a look at. Then in console it will ask if the user is sure they want to make this move. Type /yes or /no.
The confirmation board opens in sposition mode. Currently due to this being unintended support, the tab that opens with a candidate move may say 1-0 as name. The result should be ignored in an ongoing game. To clean up if the user wants, they can right click on this board tab and from popup menu that appears, close the game. On a Macbook track pad, a two finger tap simulates right click.