Hi,
The new kidzy template update is suitable for J 4, 5 & 6 you mentioned.
But after update to version 3.0.4 there is the red screen (500 hundred error). After viewing and hours of work to put just code in several files, i give up.
There is a lot of old J3 code inside several files (for example error.php, logo.php, title.php, default_url.php & default.php) what is not working well like rules as JFactory, JURI, JDocumentRendererHead, JModuleHelper & JFilterOutput.
For now i use J5.4.3 / PHP 8.4.23 / shaper_kidzy 3.0.2
Extensions System helix 3 framework & Helix 3 Ajax are already updated to 3.1.2.
Also because of the hack!!!
I don't dare update to 5.4.6 or Joomla 6 now either.
What to do?