New MS 16.4 beta firmware - many stacking fixes!

Kind of a big deal
Kind of a big deal

New MS 16.4 beta firmware - many stacking fixes!

Switch firmware versions MS 16.4 changelog


  • MS420 devices configured for this version will run MS 15.22

Ms12x alerts

  • If DAI is enabled prior to upgrading the network to MS 16, ensure that trusted ports and/or DAI-allow lists are configured prior to upgrading to avoid potential network outages.

General features

  • ACL hit counter
  • DHCPv6 and IPv6 RA guard
  • Local Status Page Packet Capture

Ms12x features

  • DAI support

Ms225/250/35x/4xx fixes

  • A stack having multiple members reboot while also having routes learned by OSPF and static may fail to correctly synchronize across stacks
  • Learned routes may fail to correctly sync to dashboard resulting in live tool information showing stale or incorrect information
  • Rebooting a stack member may result in internal stacking packets being sent out into the LAN (present since MS 15)
  • Stack member routing tables can get out of sync when attempting to delete a layer 3 interface (present since MS 15.19)
  • Stacks with layer 3 configurations may encounter a multitude of problems resulting in routes becoming stale or incorrectly updated when changes are made or if ECMP is utilized
  • The next hop route can be incorrectly updated if it's across an LACP bundle resulting in traffic loss (present since MS 14)

Ms425 fixes

  • 1Gbps ports may randomly fail and go down until the system is rebooted (present since MS 16.1)

General known issues

  • Connecting a stacking cable to a stack that is online may result in a stack member going offline (present since MS 12)
  • Switches move LACP ports to an active forwarding state if configured. This can cause loops when connecting to an MS390 or other Catalyst switches unless the bundles are configured on the MS390/Catalyst switches first. All non-catalyst ports are configured in passive LACP mode so that loops do not occur between Meraki switches (always present)

Ms120 known issues

  • Switches in extremely rare instances will experience reboots every few minutes (present since MS 11)
  • Switches may fail to provide PoE power to legacy access points (always present)

Ms125 known issues

  • The local status page cannot be accessed from the management port (always present)

Ms12x known issues

  • Ports with an odd-numbered MTU value fail to initialize (predates MS 11)

Ms210 known issues

  • Stack ports have an orange LED instead of green (present since MS 11)

Ms2xx/35x/4xx known issues

  • IPv6 multicast packets tagged for a VLAN may not be filtered correctly resulting in packets egressing into other VLANs (present since MS 14)
  • IPv6 solicited-node packets bypass port isolation (present since MS 14)
  • Switch stacks will learn MAC addresses from ports in the STP blocking state which can trigger a constant flood of MAC flaps in the event log

Ms355 known issues

  • In rare instances, stack ports fail to initialize after an upgrade (always present)

Ms35x known issues

  • Enabling Combined Power results in events being logged once per minute (present since MS 11)
  • UPoE does not negotiate over LLDP correctly (always present)
  • mGig switches will have an amber light for all physical ports that do not negotiate to the highest supported speed. Dashboard will continue showing a light green status for all ports above 100Mbps. For example, MS355 switch ports will incorrectly show an amber light for 1G, 2.5G, and 5G, but will show a green light for 10G.

Ms425 known issues

  • Stacks in rare instances will start dropping DHCP traffic on trusted ports while DAI is enabled until rebooted (present since MS 12)

Ms4xx known issues

  • When an SFP module is inserted/removed, BPDUs can be delayed leading to STP transitions in the network (predates MS 12)
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