14.8.4.1. Restrictions 
General restrictions
- Refer is not supported
-
=> Disable REFER on Lync Mediation Server
- OpenScape 4000 SoftGate doesn't support comfort noise.
Feature restrictions
- Dual forking
- Media bypass
- E911
- DNS load balancing is not supported by OpenScape 4000
- No tones on Lync Communications Server client after OpenScape 4000 station makes transfer ringing.
- For restrictions on feature basis see Section 8.4.2, “Available Features” (detailed description for every feature in each section).