.NET Framework 4.5: Features and improvements added to the common language runtime and to .NET Framework classes

Ability to limit how long the regular expression engine will attempt to resolve a regular expression before it times out.

Ability to define the culture for an application domain.

Console support for Unicode (UTF-16) encoding.

Support for versioning of cultural string ordering and comparison data.

Better performance when retrieving resources.

Zip compression improvements to reduce the size of a compressed file.

Ability to customize a reflection context to override default reflection behavior through the CustomReflectionContext class.