Following features are known limitations of Raven (GDP-08):

• Sound quality of ongoing call may be affected when internal call recording is in progress.
• Incomplete support of VOIP calls (SIP, Skype, Skype for Business or Hangouts) via Bluetooth and ported headsets. Read more.
• Calls recording is not available for VOIP calls and for calls via Bluetooth and ported headsets.
• SD cards faster than Class 4 are not supported.
• Raven connection to computer via USB 3.0 may not be reliable.
• First call on Bluetooth headset is initialized with delay after Raven was in standby for 24 hours.
• Raven may freeze after finishing a call via Bluetooth headset.