manuP

Problem:
Updating an old WPML plugin to the latest version

Solution:

1. Different versions of WPML can be downloaded from this link here, under your WPML.org account - https://wpml.org/download/wpml-multilingual-cms/?section=changelog

2. Please make sure that you first create a full website backup so that you are safe no matter what happens.

3. The oldest version you are able to download from that link is "3.8.3". After that, I recommend that you update to each new major version (3.9, 4.0, 4.1, 4.2 and 4.3).

You can also try to create a full website backup first and then update to the latest version and see what happens - it there's gonna be serious errors and not simple notifications, then please update gradually.