Late last week we released the September 2018 Preview of Quality Rollup.
Quality and Reliability
This release contains the following quality and reliability improvements.
Updated code to prevent errors regarding invalid date format when Japanese Era 4 is used with a future date 
Parsing Japanese dates having a year number exceeding the number of years in that date era will succeed instead of throwing errors 
When asynchronously reading a process output an IndexOutOfRangeException is thrown when less than a character’s worth of bytes is read at the beginning of a line 
Fix in the JIT compiler for a rare case of struct field assignments,