Hi @joneslikoro
Welcome to DHIS2 Community of Practice! 
I believe upgrading to one of the latest versions is the best decision if you are looking for a more stable and faster version compared to the versions you mentioned. The versions you mentioned are no longer supported, don’t receive any software or security updates, and are missing many of the new features.
You can have a look at the features that came with the version 40 release: Webinar on new DHIS2 software releases: v40 and Android v2.8 - #9
Note: please make sure to read the documentation before performing any upgrade, Upgrading - DHIS2 Documentation
Thanks!