If you have installed iOS 13.3, you can no longer revert to an earlier version.
The Californian firm has just stopped signing iOS 13.2.3, which means in practice that it is no longer possible to revert to this previous version of iOS, in case you have installed iOS 13.3.
A step on the part of Apple which does not aim to annoy its users, but rather to limit the risks of hacking on its iPhone. Indeed, by reducing the field of devices updated to only a few versions of its software, Apple can focus on a limited number of versions in the event of flaws or bugs to be corrected.
In recent years, Apple has continued to reduce returns to previous versions of the software. A step which unfortunately obliges the users day to wait patiently for a new update in the event of bug or technical problem.
For iPhone owners, the only version available for download is iOS 13.3, as well as for iPhone owners who can only download version 13.3 diPadOS.
An update which has only one week and which notably introduces the functionality of communication limit which, unfortunately, is not perfected. You will most certainly have to wait for iOS 13.3.1 to be able to take full advantage of this feature. This is currently available in a beta version for developers.