PostgreSQL 18 introduces UUIDv7, a new type of Universally Unique Identifier designed to address the performance issues associated with the traditional UUIDv4 when used as primary keys in databases. Unlike the random structure of UUIDv4, UUIDv7 includes a timestamp as its most significant part, allowing for natural sortability by creation time, which improves performance through efficient sequential inserts, reduced index fragmentation, and enhanced cache utilization. While UUIDv7 is advantageous for internal applications due to its orderly structure, it poses privacy concerns if exposed externally, as it reveals the creation time of records. Therefore, it is recommended to use UUIDv7 internally and employ UUIDv4 for external identifiers. The transition from UUIDv4 to UUIDv7 requires careful migration planning and consideration of system clock synchronization for accurate timestamping. Despite its benefits, users should be cautious of UUIDv7's privacy implications, making it more suitable for internal use rather than external-facing applications.