If you are talking about this CMIS capability:
capabilityChanges
Indicates what level of changes (if any) the repository exposes via the getContentChanges service.
It is not supported by Alfresco. Check output from this URL in your repository http://<repo-server>/alfresco/api/-default-/public/cmis/versions/1.1/browser and you should get something similar as a response:
{"-default-":{"repositoryId":"-default-","repositoryName":"","repositoryDescription":"","vendorName":"Alfresco","productName":"Alfresco Community","productVersion":"6.2.0 (rb65251d6-b368)","rootFolderId":"3f7919f6-9acb-483d-aa56-e760753d70d2",
"capabilities":{"capabilityContentStreamUpdatability":"anytime","capabilityChanges":"none","capabilityRenditions":"read","capabilityGetDescendants":true,"capabilityGetFolderTree":true,"capabilityMultifiling":true,"capabilityUnfiling":false,"capabilityVersionSpecificFiling":false,"capabilityPWCSearchable":false,"capabilityPWCUpdatable":true,"capabilityAllVersionsSearchable":false,"capabilityOrderBy":null,"capabilityQuery":"bothcombined","capabilityJoin":"none","capabilityACL":"manage"},"aclCapabilities":{"supportedPermissions":"both","propagation":"propagate"...Starting from Alfresco 7.0 you could use Alfresco Java SDK 5.0.0 (https://github.com/Alfresco/alfresco-java-sdk) and Alfresco Java Event API (https://github.com/Alfresco/alfresco-java-sdk/tree/develop/alfresco-java-event-api/alfresco-java-eve...).
Maybe you should check also something about custom behaviours:
https://ecmarchitect.com/alfresco-developer-series-tutorials/behaviors/tutorial/tutorial.html
https://docs.alfresco.com/content-services/6.2/develop/repo-ext-points/behavior-policies/
