OTRS is a commercial service management platform sold as managed hosting or on-premise by quote, while its old Community Edition is end of life. Pages here cover moving to self-hosted Znuny or Zammad.
Comparing commercial OTRS, sold by quote as managed hosting or on-premise, with Znuny, the GPL v3 continuation of the OTRS Community Edition: shared roots and how far the code bases have moved apart, ITSM features, release lines, support from Znuny GmbH and who runs it.
For OTRS customers willing to change tools rather than stay on an OTRS fork: Zammad's interface, channels, knowledge base and built-in OTRS migrator against OTRS's process and ITSM depth, plus licensing, hosting and support costs on each side.
Moving an OTRS Community Edition 6 or commercial OTRS installation to Znuny: the stepwise update path, since Znuny 6.5 accepts updates only from 6.4 and not directly from any OTRS version, add-on packages, custom code, database choices and testing on a copy first.
Cost of ownership by component: OTRS licensed users, base package and add-ons quoted by the vendor, or managed hosting, against Znuny with no license fee, Linux servers and a supported database, optional Znuny GmbH services, migration effort and the people who operate it.
For teams still running the ((OTRS)) Community Edition 6.x that OTRS says gets no security fixes: the three realistic paths, buying current OTRS, moving to the Znuny fork or replacing it with Zammad, and the risk of running an unpatched help desk in the meantime.
Tell us what you're working on, whether it's a deployment, an audit, a security test or a cyber range. You'll speak with an engineer who can help you scope it.