I used to have Kotak 811 CC. I contacted Customer care and inquired about whether joining fees is charged if I upgrade it to Zen CC. The First representitive said Yes I would have to pay joining fees. I had my doubts becoz he was arrogant in his response. So I called again. The Second One was Clueless. this went on 2-3 times until I was able to interact with a knowledgeable phone banking officer who confirmed that no joining fees would be charged in case of an upgrade. I recorded each conversation (highly recommended).
Then I upgraded the CC to Zen Paid. No Joining fees was charged to me