The Security.stripInaccessible security feature for field-level data protection has moved from pilot to beta, supports subqueries, and can be used in production orgs. Callout processing time is excluded when calculating the concurrent long-running request limit. Apex introduces System methods to recalculate formula fields, and a Type method to detect type compatibility without class instantiation. The new ApexSettings metadata type augments Apex testing.
For more information on these enhancements, see the Apex Developer Guide.