Is there a plan to release a new Windows Server On ARM Insider Preview?

You are asking whether Microsoft will replace expired ARM64 Server preview build 26501.1000 with a newer image. There is no public commitment or release date in Windows Server Insider documentation, so promising another ARM64 build would be misleading. Check the Windows Insider Preview Downloads page linked from the Windows Server Insider getting-started documentation; the architectures shown there are what Microsoft is distributing. Because Insider builds expire, build 26501.1000 should not remain in service or be worked around by changing the clock. Remove it from any production or security-sensitive role and preserve only needed test artifacts. If the downloads page offers no newer ARM64 media, use a supported Windows Server release on x64 for ongoing work, or keep ARM testing isolated until Microsoft publishes replacement media. Submit the scenario and hardware details through Feedback Hub, since Microsoft uses Insider feedback to assess demand, but feedback does not constitute a roadmap commitment.