Reading, hiding or changing WordPress version information. NOT about specific versions of WordPress or update problems.
The current WordPress version is stored in a variable
wp-includes/version.php. You can
include that file to get an unaltered version. Do not use
require_once, because that would code that is running later.
It looks like the format of semantic versioning, it is also compatible with PHP's
version_compare(), but it doesn't follow the rules of semantic versioning: The second number is just treated like a counter from 0 to 9. So after 3.9 cam 4.0, but there were not more (important) changes than between 3.8 and 3.9.
By default WordPress announces its version in a
meta element with the
name="generator". This can be turned off.
The WP version number is also used as a default value for a parameter in enqueued resources (scripts and styleheets). This can be turned off to.
Do not use this tag to address a specific WP versions or update problems.