2.0 Success. 
2.1 Success but fallback taken on one or more property  values. 
2.2 Success, invalid property ignored. 
2.3 Success, invalid property parameter ignored.  
2.4 Success, unknown non-standard property ignored. 
2.5 Success, unknown non-standard property value  ignored. 
2.6 Success, invalid calendar component ignored.   
2.7 Success, request forwarded to Calendar User.  
2.8 Success, repeating event ignored. Scheduled as a  single component. 
2.9 Success, truncated end date time to date boundary. 
2.10 Success, repeating VTODO ignored. Scheduled as a  single VTODO. 
2.11 Success, unbounded RRULE clipped at some finite  number of instances  
3.0 Invalid property name.  
3.1 Invalid property value.  
3.2 Invalid property parameter.   
3.3 Invalid property parameter value.  
3.4 Invalid calendar component sequence.   
3.5 Invalid date or time.  
3.6 Invalid rule.  
3.7 Invalid Calendar User.  
3.8 No authority.   
3.9 Unsupported version.   
3.10 Request entity too large. 
3.11 Required component or property missing. 
3.12 Unknown component or property found 
3.13 Unsupported component or property found 
3.14 Unsupported capability  
4.0 Event conflict. Date/time is busy.  
5.0 Request MAY supported.  
5.1 Service unavailable.  
5.2 Invalid calendar service.  
5.3 No scheduling support for user.