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- Since our connector works for SharePoint Online and on-premise as well there is required a technical solution required that is appropriate for both systems.
- In SharePoint Online WSP solutions are not allowed at all - so this option was a No-Gowas not an option.
- Furthermore WSP solutions are "old-style" and already now kind of "deprecated".
- WSP solutions surely will not be allowed anymore in future versions of SharePoint server as well (in SharePoint 2019 sandboxed WSP solutions are already marked as deprecated and are not allowed if they contain code).
- addAdd-ins are a lot more secure than WSP solutions.
- see See also Five reasons to avoid ‘Full Trust’ solutions in SharePoint
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