Hi @ajin0093
This is an upgrade project which needs proper planning and approach to make a decision. It is not recommended to replicate content from a lower AEM version to a higher AEM version.
Start from here to get an understanding of the AEM upgrade. You will understand the few additional steps which you might need to do as per Adobe recommendation like repo restructuring.
https://docs.adobe.com/content/help/en/experience-manager-65/deploying/upgrading/upgrade.html
Coming back to your question, there can be two approaches
Recommended Approach(in-place upgrade):
The best approach would be to do the in-place upgrade which will move your content from lower to higher AEM version. Suppose if you want to upgrade your development and production AEM 6.3 version to 6.5 then it should be like:
AEM-Dev-Author 6.3 --------in-place upgrade-------> AEM-Dev-Author 6.5
AEM-Dev-Publish1-6.3 --------in-place upgrade------->AEM-Dev-Publish1-6.5
AEM-Dev-Publish2-6.3 --------in-place upgrade------->AEM-Dev-Publish2-6.5
AEM-Prod-Author 6.3 --------in-place upgrade-------> AEM-Prod Author-6.5
AEM-Prod-Publish1-6.3 --------in-place upgrade------->AEM-Prod Publish1-6.5
The advantage of this approach will be your custom users and groups will be migrated as it is corresponding to the environment.You don't need to take care of anything separately.
Documentation for in-place upgrade: https://docs.adobe.com/content/help/en/experience-manager-65/deploying/upgrading/in-place-upgrade.ht...
Alternate Approach(package based approach- export and import):
Another approach would be exporting all the content package from AEM-6.3 and importing it in 6.5.
You can either create packages from AEM source[AEM 6.3] package manager and import it in the target AEM higher version[AEM 6.5] or alternatively you can use the VLT tool to do so [https://helpx.adobe.com/in/experience-manager/6-3/sites/developing/using/ht-vlttool.html].
But in this approach, you have to take care of custom users and groups. Creating a user package is slightly tricky - you can use ACS package to do so otherwise google it, you will get numerous blogs by AEM Guru's to guide you.
Regards,
Arpit Varshney