Can one modify KNIME source-code and logo for commercial usage?

Hello KNIME Team,

Had a couple of questions on the GPL licensing terms. Would appreciate if anyone could help out on these:

1. Can one modify the source-code of KNIME, as well as its logo and use it for commercial purposes? i.e. can one modify the code and offer it as a commercial data-analytics platform, where customers are charged for consultancy, or developing custom analytics /ML models etc.

The source-code of the modified platform would be released to the clients, as per the GPL licensing terms.

2 If any custom extensions are developed, would the source of these custom extension also be need to be released to customers?

Any pointers on this would be very helpful. Many thanks in advance!