How to override apps files ?

I am trying to override the stream output for apps and i need a small tip

I noticed that the stream output is controlled by apps theme files located under the directory shown below

/media/com_easysocial/apps/user/

For example, the EasyDiscuss app stream is controlled by files located under this directory

/media/com_easysocial/apps/user/discuss/themes/default/streams/

The question is how to override/modify some app files in order to avoid any issues with future updates ?

For example, if i wany to override the file below

/media/com_easysocial/apps/user/discuss/themes/default/streams/create.title.php

How to proceed ?
Of course i can modify the file directly in order to obtain the output i want but i assume on future updates i will loose my changes.