Guys i waited months and months but no fix for this problem. There are delay notifications for whatsapp, Facebook, gmail, email, etc.., delays of 15/20 minutes. I tried everything, get all permission to app, allow popup, put in autostart, block in task manager, install the push notification fixer app, but nothing works. I see that this bug is present in various devices, Galaxy Nexus, Nexus 4, Galaxy S2, Xiaomi Mi2S. If someone can communicate with xiaomi dev, please report this bug, thanks.