SRFA

Thank you. 🙂
1. I might need admin access to troubleshoot this further. I can't reproduce this currently.
2. This should be a quick fix, do you have ftp access to your ipb files? Might be able to put together a patch.
All saved, probably won't be included before IPB 4.5 now but will look at each suggestion in future versions.

No, thanks. I will continue to correct false statements as I always do. It is up to you to stay ignorant about these matters or decide to learn something new. 
For other, more open French speakers I repeat the link again:
https://www.brunobernard.com/des-textes-plus-elegants-avec-les-apostrophes-typographiques/

Hi Mike! In the end it had nothing to do with the PHP/MySQL version. But I wanted to let you know that I finally solved the problem! 
I feel reaaaaally stupid and just don't know how I could miss that, but there were, indeed, old entries prefixed by aw_ in the sys_conf_settings tables. Probably inherited from an previous version (our database has a long and troubled history). I had checked 10 times yet but... had simply missed the "next page" button in phpmyadmin... and finally had an epiphany by accessing the tables through the ACP instead of phpmyadmin (a fresh look on things!) These entries were probably locked (considered as belonging to another app?), and were then preventing the new version of the app to write its information properly. I manually deleted all these entries before re-installing the app, and everything works perfectly now.
Many, many thanks again for your help, patience, and your great app 
 

That's just the modules of the app. The auto welcome doesn't need any because it's just utilizing hooks/extensions.
I don't foresee any possible link unfortunately.
Could you try uninstalling again, unzip the the "autowelcome.tar" into a folder called "autowelcome". Then upload that folder to the /applications/ folder and install from the admin cp that way? Perhaps the internal unzip and install is messing with the settings data somehow.
Thanks for that information. Anyone else with this problem can confirm it's consistently reproduced with social media signups?
Edit: I take it your also using the latest version of IPB?

Problem solved with upgrade to .1! I should have tried this from the beginning, it was crystal clear explained in the release notes. 
Sorry to have spoilt your time and many thanks for your help, you're really great guys!!

Problem solved with upgrade to .1! I should have tried this from the beginning, it was crystal clear explained in the release notes. 
Sorry to have spoilt your time and many thanks for your help, you're really great guys!!

@Adriano Faria Look at this. 

Disable all plugins to see if the problem goes away. Then you have to enable them one by one to see what’s causing it. 

1.0.16 has an issue indeed, that’s why .1 was released. 

Member Map
View File IPS 4.4 ONLY 
For IPS 4.3, use version 3.5.7
Member Map is an application that allows your users to put their (Exact or approx) location onto an interactive map. Member Map has a permission model so you can limit which groups can add to the map.

As an administrator you have the ability to create custom groups where your community (when allowed) can place other markers in the map, for example if they would like to post the location of an upcoming meet, exhibits, shops, etc.
For developers
If you are a developer and you store location data in your app that you'd like to show on the map, you can now do so creating a membermap/Mapmarkers extension. Instruction on how to use it is included in the auto-generated file.
Submitter Martin A. Submitted 03/18/2010 Category Member Extensions Compatibility 4.4  

That's a core feature.