Need guidance on adjusting sleep schedule

We finally got my little in his crib this past November. Currently he is 10 months old. He will be 11 months on February the 3rd. He currently is on the schedule of 3.5/3.5/4. We cap his naps at 2.5 hours total. He has been waking up for the past couple of weeks every night at 11pm. We usually give him a bottle to settle him back down. How do we get out of this. What schedule adjustments should I be making?