Hello syedhannan27,   Looks like E5-26xx v2  support was added in BIOS version: 2.7.0   But update to the latest before upgrading processor: Dell Server BIOS PowerEdge R520 Version 2.9.0 [URL]   Please let me know if this helps.
My company are planning to upgrade our PowerEdge R520 processor from E5-2407 to E5-2495v2.The question is, can R520 support E5-2695v2 processor?based on r520 owner manual show that it can support "One or two Intel Xeon processor E5-2400 and E5-2400 v2 product family" refer R520 Owner manual . If yes, can I just upgrade the processor or I need to upgrade BIOS firmware that support the processor? If E5-2695v2 processor is not supported can someone suggest or give a list of processor that R520 support. Thanks. 
Can PowerEdge R520 upgrade processor to E5-2695v2?