Should Wordpress be updated to version 4.0?

1. For example, here , and the original source is better (and generally I strongly recommend reading the code to anyone who works with WP).

2. Most likely no. If only you are using a very old theme that has not been updated for a very long time and uses some of the functions of the WP core that have been thrown out in this release. But WP is pretty damn conservative, something rarely happens.

3. There is.

Update WP is necessary. WP is a very popular CMS, that's why it is searched, found and fixed bugs, including serious ones, in general quite often (it seems that in every update there is something about security). If WP is not updated, you will remain with your time-tested vulnerabilities, which have already been accurately identified and widely used by good people (and, worse, good robots) for not very good purposes. The same goes for its plugins and themes.

Problems with updating the WP core (or themes, or plugins) can arise if you yourself have made changes to the WP core, themes, or plugins. Your changes will simply be overwritten by the update. Therefore, WP / plugins / themes cannot be edited in the most obvious way (just take and edit), you need to use more clever methods. To change the behavior of the WP core, you need to use plugins, to change themes, there is a mechanism for child themes (a child theme is created that derives from the main one, and changes are made to it).

In general, if WP is cooked correctly, then updates are a completely painless process. If WP doesn’t cook correctly, then you need to learn to cook it correctly (or not to use it), and not to sit without upgrades.

By the way, WP is updated very often (and this is correct), so get used to it.

PS And make a backup before upgrading, anyway, an extra backup is not superfluous.