Currently I have Captivate 2019 V188.8.131.526 and my colleagues have captivate 2019 V184.108.40.2069. If they create a project I cannot open it as I get a compatibility error, and if I create a project which they then review and save it becomes corrupt for me. I know captivate is not forward compatible but is it really this touchy, I mean its the same overall version ie. 2019 just a slight difference on the version number ?
There is no compatibility between 11.0 and 11.5. Your colleagues should be able to open your projects (and update them). But at that moment the project is a 11.5 project and you cannot open it anymore. Any reason why you didn't update, it is free?