The recent version of emacs seems to have eliminated my preferred formatting mode for plain text, parident.

When I hit tab at the beginning of a line emacs inserted a tab; re-formatting with ctrl-q kept it. Now it does nothing and in every mode I have tried whatever gets inserted (which isn't always the same thing in the same mode; sometimes it's 3 spaces; sometimes it's a tab and 3 spaces) gets wiped out by a re-format and my new paragraph, which I intended a tab-indentation to mark, is concatenated with the previous paragraph.

What version of emacs? It's there in 23, but there is a version 24.

24.5, the version just released in the latest Slackware. The last version that worked is 24.3

parident is short for paragraph-indent-minor-mode, which one can still invoke, but doesn't work the same way and doesn't show up as the mode on the status line. I've tried every other mode I have found: none of them work as the old parident did.

I know the mode but I don't use it. I think you can specify the different behaviors like spaces for tabs and the length of the indents per mode. Sounds like they changed the defaults for that mode or stopped supporting it.

I hope so. I asked here because I have looked at everything that I can find in 'info emacs' and emacs help and either not found how to do these things or what I found didn't work as described. (It seems the docs are behindhand.) The most important matter for me is making emacs treat newline-tab as the beginning of a paragraph, to stop erasing them with fill-region and fill-paragraph

The upgrade from 24.3 to 24.4 changed the file structure of the emacs package a lot.