qTranslate WP 4.0

Try this:

That’s a bug in the qtranslate system, it should only compare the minor version (it’s compatible with 3.8.x) instead of the patch version (which is distributed with no notice whatsoever and should’t break compatibility).

This happens every time a new release is out. Because this is just a patch version, you can safely trick qtranslate into thinking that it is configured to run with 3.8.3. Change qtranslate.php line 90 from:
define(‘QT_SUPPORTED_WP_VERSION’, ‘3.8.2’); to define(‘QT_SUPPORTED_WP_VERSION’, ‘3.8.3’);

Fill out the version you have.
And thank iggyvolz here:
https://wordpress.org/support/topic/autoupdate-to-wp-383-has-disabled-qtranslate-plugin?replies=17

If you get in trouble with the visual editor, do this:

https://gist.github.com/warenhaus/10990386

Replace qtranslate_hooks.php, qtranslate_javascript.php and qtranslate_wphacks.php with the code found in the link.

And thank aramaz here:
https://wordpress.org/support/topic/heres-a-fix-i-found-for-the-bug-with-visual-editor-in-wordpress-39

Good luck!