Update Merge
Third-party developers have the option of supporting additional merge options, allowing their customers to update individual parts of a Project file, thus improving the overall workflow.
The following options may be available:
When enabling this checkbox, a new Project will be created without updating the currently opened Project in Cinema 4D.
When enabling this checkbox, Cinema 4D will cross reference the geometry contained within the merge Project with that of the currently opened Project in Cinema 4D. If a match is found, the geometry in Cinema 4D will be updated.
Note that UVW or Selection tags have to be modified for geometry that has to be updated, even though Material is disabled. This will be necessary if the point or polygon count of the object to be updated changes.
When enabling this check box, Cinema 4D will cross reference the materials contained within the merge Project with that of the currently opened Project in Cinema 4D. If a match is found, the materials in Cinema 4D will be updated.
The following applies for identical material IDs: If an imported material was modified (e.g., improved) in Cinema 4D, this material will be used, regardless if the material was modified in the third-party application in the meantime. The Cinema 4D material will have priority.
If a new, imported material includes textures, a prompt will ask if the textures should be copied to the Project’s search path. You should always confirm this prompt with "Yes" so the textures can be later found. If the Project has not yet been saved, the textures will in part be saved to temporary directories (the Project should then be saved using the 
Save Project with Assets...
Note that no materials will be adapted or modified if this option is disabled.
If enabled, Cinema 4Dwill cross reference the layer parameters contained within the merge scene with that of the currently opened Project in Cinema 4D. If a match is found, the parameters are updated with the exception of the layer name.
If enabled, Cinema 4D will cross reference the individual lights contained within the merge Project with that of the currently opened Project in Cinema 4D. If a match is found, the individual lights in Cinema 4D will be updated.
If enabled, Cinema 4D will cross reference the cameras contained within the merge Project with that of the currently opened Project in Cinema 4D. If a match is found, the cameras in Cinema 4D will be updated.
If enabled, Cinema 4D will cross reference the Physical Sky contained within the merge Project with that of the currently opened Project in Cinema 4D. If a match is found, the Physical Sky object in Cinema 4D will be updated.
If certain or all options have been greyed out, the third party application does not offer support for the improved functionality and the old behavior will apply.
The third party application determines which options are checked or unchecked by default, depending on their preferences.
In the list below you will find information regarding file version.