(Compiled from latest sources, on Ubuntu 16)

Just a quick question: do the -incremental search commands using with command-prompt -i support regexp? It didn't work when I tried and just wanted to confirm if it's a user error on my part or if this is something not supported? Regex search works perfectly fine with normal search commands (search-forward & search-backward). Somehow assumed incremental would work since command-prompt -i executes the command as input changes per help doc. Fwiw, this is what I have for mapping to do incremental search:
bind-key -n C-s copy-mode -e \; send -X start-of-line \; command-prompt -i -p "search up:" "send -X search-backward-incremental \"%%%\""

Help text doesn't seem to explicitly call this out one way or the other:

The search commands come in several varieties: ‘search-forward’ and ‘search-backward’ search for a regular expression; the ‘-text’ variants search for a plain text string rather than a regular expression; -incremental’ perform an incremental search and expect to be used with the -i flag to the command-prompt command

Thank you.