This week I travelled with a new passport and OCI with the old passport number for the first time. Big mess, will get the OCI booklet reissued asap:

Departing to India all the systems marked me as having no visa because the (new) passport number was not linked to any visa. Major confusion and no note in checkin systems possible.

Each time you have to fuss around with two passports and the booklet.

Leaving the BoI officer decided to take a good look at my old passport (since there was no one else to check) and looked at all the pages. He was very curious that I had been to China so often ... all questions were posed in Hindi which I tried my best to respond to in my garbled Tom Alter hindi...