Hi An
First of all it's a very bad thing to change the code of a framework. With this action you will have problems every time you need to do an update. Ok, you want to stay on the version 1.0.1 but what if this version gets incompatible with Primefaces itself? But this only as side note.
I think it should be still possible to use your own serenity theme, even whit the version 1.0.1. But for this you need your own theme name. If you have your WEB-INF/lib folder first of all don't delete the normal serenity jars, you can put your own jars beside them. E.g:
![alt text][1]
May you need to repackage the Serenity java classes in the theme jar too. (http://repackage.org/)
To use your theme now import them in your template.xhtml file:
![alt text][2]
Kind regards
Lukas
[1]: https://answers.axonivy.com/upfiles/Screenshot_from_2019-10-10_09-30-58.pnghttps://answers.axonivy.com/upfiles/Screenshot_from_2019-10-10_09-40-26.png
[2]: https://answers.axonivy.com/upfiles/Screenshot_from_2019-10-10_09-39-36.png
