POA-87534 After upgrade to 5.5.7, in CCP buttons in navbar use different skin than on 5.5.6
Hotfix can be downloaded here.
Use pa_updates_installer to install this hotfix. Also this hotfix will be installed automatically during upgrade to POA 5.5.7 via pa_updates_installer. To install hotfix manually obtain its distributive from the link above and follow instructions found in file UPDATE.txt of distributive.