Perhaps the best solution, for now, would be to install the older version (5.2.14), following the instructions for manual update, but I cannot find where to download it from.

5.2.14 can be found here: github.com/LimeSurvey/LimeSurvey/releases/tag/5.2.14%2B220214

Other older releases are here: github.com/LimeSurvey/LimeSurvey/tags

Make sure you have your config.php from your last working version. (/limesurvey/application/config/config.php)

djehuti wrote:

Make sure you have your config.php from your last working version. (/limesurvey/application/config/config.php)
 

Not necessary : if you choose the previous DB when install : LimeSurvey check if need updgrade or not and don't touch if uneeded .

Sometimes it's best to do the install : then checking if necessary PHP module are here .

Finally, I followed a tip by Ollehar from the bugs reporting platform, to download the 5.3.1 zip file and copy from there the missing file(s). This did the trick, and at last, I got the installation working without the "globalsettings.php" problem. Everything seems normal (for now).

Many thanks for the support!