The execution of cmk-update-agent could abort showing the following errors with Check_MK version shipping werk #4565 (1.4.0p11 only):
invalid signature #.. ERROR No valid signature found.
This Error message would also be displayed directly on cmdline when running cmk-update-agent manually or within the corresponding Check_MK Service when cmk-update-agent is executed as a plugin
The error can occur on hosts under the following circumstances: - An new agent got baked for the host after updating to Check_MK 1.4.0p11 - cmk-update-agent uses curl for server communications, i.e. there is no python-requests installed on the host. - this error does not occur on Windows hosts (hence python-requests is packaged here)
After updating Check_MK and rebaking your agents, it is also required to reinstall the Check_MK Agent on affected hosts.