Anna, some new channels like BFlix, Aastha Bhajan etc. had old logo even though they were added after the start of new logo implementation process.
Airtel Digital TV backend team added new logo across channels in a phased manner. They selected a transponder , replaced the logo on all channels present on it & then moved on to next transponder to perform this task. Hence any new channel which was added on a transponder where this task was not started at that point, it had the old logo which was later replaced with new logo