By default each user has voicemail enabled. To disable voicemail user has to check the 'off' button in Settings menu.
The received voice messages can be found in recent calls menu.
Go to Recent Calls menu, click on any Missed-Call log to see its details. Click on the Play button to hear your voicemail. The duration of each Voicemail message is also shown next to each message.
A message is marked as new until you open the list of the recent calls menu and click on the message. This information is stored on the server side.
Message Waiting Indicator (MWI)
The dialer uses subscription to the MWI mechanism in order to notify the user about new voicemails. When a caller leaves a voicemail the server immediately sends notification to the user. If the user is not registered the PUSH is sent. When the dialer registers again the list of newly left messages is downloaded and a badge with a number of new voicemails is shown on the menu icon on the recent menu.
Voicemail to email
This feature delivers voice messages to your email box in form of an mp3 file. To enable it just enter the email address in the voicemail settings. The voicemail to file conversion is realized on the server side so even if your dialer is closed or offline you will still be able to receive emails with attachments.