IPSO 6.0 was announced by Nokia in relation to the IP2450 and IP690 hardware. It is based on FreeBSD 6.x. Its primary advantage over IPSO 4.x are improved memory management, performance, scheduling, threading, POSIX-compliance, and other operating system features. IPSO 6.0.7 was released in 2009 for IP690 and IP2450 with CoreXL (multi-core) support. IPSO 6.1 contains other enhancements from FreeBSD 6.x but without CoreXL support. Because of the step change, Nokia advertised that IPSO 4.2, 6.07 and 6.1 will run alongside each other for a period of time. When Check Point acquired Nokia IP appliance business, 6.07 and 6.1 development branches were merged and combined to 6.2.