Unlike the Softphone premium client, the Softphone standard client is included in the 1&1 Business Phone Plus tariff.
An upgrade to the Softphone premium client is possible at any time and causes monthly costs. Prices can be found in the current price list.
| Functional overview Softphone Windows |  |  |
| Softphone standard | Softphone premium | |
| Encryption via SRTP (from version 8.0.0) | ✓ | ✓ |
| DND (Do not disturb) button | ✓ | ✓ |
| Selection of the input/output audio device | ✓ | ✓ |
| Adding, changing, deleting of contacts | ✓ | ✓ |
| Export and import of contacts via a CSV file | ✓ | ✓ |
| Defining individual contact groups | ✓ | ✓ |
| Call history (missed, placed and received calls) | ✓ | ✓ |
| Call control from Outlook via an Outlook AddIn | ✓ | ✓ |
| BFL's | - | ✓ |
| TAPI | - | ✓ |
| ActionURL's | - | ✓ |
| Access to the PBX phone book | - | ✓ |
| Switch between the Classic GUI and the Office GUI | - | ✓ |
| Automatic conferences | - | ✓ |
| Automatic call acceptance | - | ✓ |
| MWI | - | ✓ |
| Banned telephone numbers | - | ✓ |
| Recordings | - | ✓ |
| Practical operation via a knocking menu | - | ✓ |
| Defining individual hotkeys (key combination and hotkey dial) | - | ✓ |
| Drag & Drop feature for dialling telephone numbers, attended / unattended call forwarding | - | ✓ |
| Integration of function keys into the contacts directory | - | ✓ |
| Call control features | ||
| Call waiting/ toggling | ✓ | ✓ |
| Ad-hoc conference | - | ✓ |
| Accepting and ending calls via Plantronics and Sennheiser headsets | ✓ | ✓ |
| Mute and volume control via Plantronics headsets and Sennheiser headsets | ✓ | ✓ |
| Ignoring | ✓ | ✓ |
| Banning | ✓ | ✓ |
| Compatibility | ||
| Windows Vista, 7, 8 and 10 (32 & 64 bit) | ✓ | ✓ |
| Outlook 2016 (32bit & 64bit) | ✓ | ✓ |
| Outlook 2013 (32bit & 64bit) | ✓ | ✓ |
| Outlook 2010 (32bit & 64bit) | ✓ | ✓ |
| Outlook 2007 | ✓ | ✓ |
| Outlook 2003 | ✓ | ✓ |
| Outlook XP | - | ✓ |
| Outlook 2002 | - | ✓ |
| Outlook 2000 | - | ✓ |