What is the version of Java you are having and did you see any errors in the log files (error.log) ? What is the process you are following to upgrade ? Is it installing Service pack 8 on plan version of AEM 6.5 ?

Hi, Can you check by expanding the bundles and see whether there are any unresolved bundles which has version conflicts ? Also, check whether the uber jar was updated to the correct AEM version. 

Hi, Usually html injection can happen by either url or user input data. We need to check for the html tags and encode them to make sure they are consider as string instead of html tags. Take a look at below link for additional details https://www.softwaretestinghelp.com/html-injection-tutorial/

Can you check, that the service is properly registered within OSGI? Go to https://<host>:<port>/system/console/components and look for your class. If it is active and still getting replicator as null, share your complete file for checking further.

You can take a look at this article : https://www.flexibledesigns.rs/activate-a-page-programmatically/

Is your code have @reference added to the replicator  @Referenceprivate Replicator replicator;

Hi, See whether the user (session) is having replication access and check there are any exceptions in error.log like replicator is not null.  

Hi, Try to add a Custom Process Step in "Dam Upload Asset" (/libs/cq/workflow/content/console.html) workflow which checks the size of uploaded image and allowed size for the folder and continue if satisfies or stop the upload process Hope this helps!

Hi, Refer below node which displays the option in nav only if the user has read access to /etc/workflow/models /libs/wcm/core/content/sites/jcr:content/actions/selection/create/items/createworkflow/granite:rendercondition /libs/cq/gui/components/renderconditions/canreadworkflowmodels/canreadworkflow...

Hi, If you are adding a field in dialog where authors enters, it is good to validate on dialog submit instead of page