@Crocker : Mainly if you see the Mx 15 feature highlights which is not there in 14.51 Fixed issue in 15.1 which was there in 14 BGP-learned routes will no longer be exported via OSPF Features added in 15.11 Added the ability to download diagnostic information from the local status page for the Meraki Support team to examine Added support for the MX67(C,W), MX68(W,CW), and Z3C platforms on MX 15 Added support for reporting of flows blocked by layer 7 firewall rules to syslog Added firmware support for whitelisting domain from being redirected to Umbrella Features added in 15.42.1 Added support for Cisco Umbrella integration Added support for establishing non-Meraki VPN tunnels using IKEv2 Added support for configuring source-based default routes Local breakout of SaaS applications to use public Internet links instead of Auto VPN tunnels. L3 breakout policies are available with all license tiers. Smart application breakouts are available with the Secure SD-WAN Plus license. More stability for Z3 devices all versions in between are beta versions.
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