Hello.
Open Real Estate CMS is an open-source software.
You can make changes in the code yourself and add new features or adjust the current ones.
"2.3. User is eligible to make any changes in the Product distributives in his sole discretion. However, further use of the Product should be performed in accordance to the Аgreement and accounting the copyright. In case User makes any amendments, the Author doesn't bear responsibility for the Product performance."
Read more:
https://open-real-estate.info/en/license