You cannot directly upgrade or migrate from 1.6.1 to 2.4.0/2.4.1 .
Please follow the below steps to migrate from 1.6.1 to 2.4.1
Install 1.6.3-r39 package on top of 1.6.1 (Package Can be found in support site)
Once 1.6.3 installation is done take a database export and shutdown the server .
Install 2.1.0-r22 in a new server and give the same IP as your old server and import the 1.6.3 backup. This step makes sure that your devices will come to the new server having the same On Premises server IP.
wait for sometime until the migration completes and the Migration banner is not shown in the cnMAestro GUI.
Once migration is completed try to do ova upgrade to 2.3.0-r28 from Application->Server->Operations page in the Software update OVA section.
wait for sometime until the migration completes and the Migration banner is not shown in the cnMAestro GUI.
Once migration is completed try to do ova upgrade to 2.4.1-r10 from Application->Server->Operations page in the Software update OVA section.
You can also follow the steps for database import and export in the user guide of cnMaestro.
Please raise a support ticket if you need any help with this upgrade.