Who is developing plugins for Redmine?

Question

CRM

Who can or can tell people who develop plugins for crm Redmine.

For those who develop themselves
Important parameters in CRM:
Ticket system, creating events, setting tasks for employees, connecting PBX and Push notification system about scheduled events and missed calls.
If you're interested, please email...
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If these CRM Parameters can be implemented in another CRM, we'll listen to your suggestion. CRM must be installed on Our server. One time payment