In SQL Server 2014, you can have 8 secondary replicas, it was 4 in SQL 2012
Ref: What’s New (DB Engine) SQL Server 2014 – http://msdn.microsoft.com/en-us/library/bb510411%28v=sql.120%29.aspx#DataFiles
What is Cardinality Estimation? This is new feature in SQL Server 2014: The cardinality estimation logic, called the cardinality estimator, is re-designed in SQL Server 2014 to improve the quality of query plans, and therefore to improve query performance.
Traceflag 9481 forces Query optimizer to use old version while generating Query Plan (When DB Compatibility level is 120).
Traceflag 2312 forces Query optimizer to use New version while generating Query Plan (When DB Compatibility level is 110).
Ooops, this seems to be a documentation bug, the flag numbers are interchanged 😦 Could check the documentation once it is updated
What is new in SQL Server 2014 Database Engine: http://msdn.microsoft.com/en-us/library/bb510411(v=sql.120)