My Zend framework version is 2.0.5
In the original project, I hope to be able to easily use the php 7.3 version
Zend framework 2.0.5 or 2.x.x supports php 7.3?
or upgrate zf3?
Besides the fact that ZF 2.* is deprecated since 2018, your version (2.0.5) is NINE YEARS OLD
I'd be more concerned about using such an old version, rather than be concerned if it is compatible with PHP 7.3.
Using PHP 7.3 is (afaik) possible, but maybe you'll need to make just few edits in your code (and in the library) for specific usecases.
Howevery, I'll suggest you to upgrade to zf3 as soon as possible.