It is not possible to assign IP address to VPS via CCP > VPS > Network Settings > Add IPv4 address. Despite "Configuring the subscription..." notification, new address is not assigned.
The following error message could be found in browser console:
Uncaught TypeError: Cannot read property 'aps' of undefined at doReconfigure (VM343 network-edit.js:174)
CCPv1 does not provide property
aps.context.user which is used by VPS network configuration scripts. It is recognized as software-related issue CCU-15491: 'VPS NG Impossible to add IP address to VPS via CCPv1'.
Workaround for this issue exists, but it implies modification of application files. Please contact your Technical Account manager in order to acquire it and get more details about status of CCU-15491.