Hi Jiri,
For Kernel SP, please go to Menu -> System -> Status... -> Click on "Arrow" button next to navigate button at bottom right corner of popup and you will find "Sup.Pkg lvl" info.
Please refer to note#1848339 for details on minimum requirement of Kernel (atleast SP 35 or more) and Basis 740 (atleast latest Release level which is SP08 on service market place). It is recommended to have both source and target system above this level. Please recheck the issue after applying required patches.
Thanks
Chinthan