Switch from Prolexis to LanguageTool : is it possible to add personalized rules?

There are some very important rules that are missing or that disappeared from LanguageTool.
I would like to add them manually : should it be something possible ?

One of the rules I’m missing are the non-breaking spaces (espaces insécables) that are no longer corrected.

Of course, I’m aware that Prolexis is a professional tool for editors.
But my usage of Prolexis let me switch to LanguageTool…

Could you give an example of a rule not matching anymore? Maybe it has been moved to “picky” mode. We rarely remove rules, unless we’re sure they are really not useful.

To answer your question, if the rule is very simple without conditions (which I guess it’s not), the style guide might help. Otherwise, you’d need to host your own LT, but that way you won’t have AI-based rules.

The most important rules that I need in French and used in the past when I started my Premium account is :

  1. Replace standard spaces by non-breaking spaces before : ; ? ! » and after «
  2. replace the Ascii quotation marks (") by “chevrons” (double angle quotation marks) as quotation marks, such as « this ».

There are many other errors depending on the days…
I was a highly enthusiastic LanguageTool user, and I remain a proud Premium member (hopefully for long years). However, I must express my dissatisfaction with the lack of transparency regarding the beneficial rules that were abruptly removed. I already wrote about that but without clear answers.