which TIA Portal Version you use?

in newer TIA Version (V14 SP1 or above) some old panels no longer supported

you must then first migrate the WinCC Flex project to TIA V13 SP2 and change the Device here and then Update the project with the comfort panel to the version of TIA you need.

TIA V13 SP2 can work with the licence of a newer TIA Version.

in this version the MP370 not supported

and if i remember the MP370 was never supported in TIA, you must first change the Device to MP377 12" , then  migrate to TIA V13 SP2 and then update to TIA V17.

Hello

yes the way ChristophD wrote is correct.

Here are some additional information:

https://support.industry.siemens.com/cs/ww/en/view/49752044

https://support.industry.siemens.com/cs/ww/en/view/76878921

Bye Murof

but the wincc is integrated in step7 project

so you can migrate the complete project or de-integrate the project in winccflex (ther is a menu in winccflex where you can do that)

Hello pankay_054

if you have trouble with Migration directly in TIA Portal you can also use the migration tool and do it in two steps:

https://support.industry.siemens.com/cs/ww/en/view/58638200

Bye Murof