The following tables displays the release support matrix for fast software upgrade.

The following restrictions are applicable to both standalone and stacked device:

• Before you perform xFSU, you need to check if the FPGA version is compatible. Perform the steps as follows to check the FPGA version.

  1. Use the show version | inc IOS XE command to check your software version.

  2. If your current software version is Cisco IOS XE 17.6.7 or earlier, Cisco IOS XE 17.9.4 or earlier, Cisco IOS XE 17.12.4, or Cisco IOS XE 17.15.2 or earlier you need to upgrade your software version.

     You need to upgrade the software in install mode.

     Refer this table to know if you need to upgrade to your software version.

     Current software version	Upgraded software version
     Cisco IOS XE 17.6.1 to Cisco IOS XE 17.6.7	Cisco IOS XE 17.12.5, Cisco IOS XE 17.15.4, or Cisco IOS XE 17.18.1.
     Cisco IOS XE 17.9.1 to Cisco IOS XE 17.9.4	Cisco IOS XE 17.12.5, Cisco IOS XE 17.15.4, or Cisco IOS XE 17.18.1.
     Cisco IOS XE 17.12.4	Cisco IOS XE 17.12.5, Cisco IOS XE 17.15.4, or Cisco IOS XE 17.18.1.
     Cisco IOS XE 17.15.1 and Cisco IOS XE 17.15.2	Cisco IOS XE 17.15.4, or Cisco IOS XE 17.18.1.

  3. If your current software version is Cisco IOS XE 17.6.8, Cisco IOS XE 17.9.5, Cisco IOS XE 17.12.5, Cisco IOS XE 17.15.3, Cisco IOS XE 17.15.4, use the show xfsu eligibility command to check if the FPGA version is compatible.

     The following example shows if FPGA is compatible after running the show xfsu eligibility command.

     Device# show xfsu eligibility
     Eligibility Check      Status
     =======================
     Autoboot Enabled:       Yes
     Install Mode:           Yes
     Supported FPGA:         Yes 
     MacSec:                 Eligible
     Spanning Tree:          Eligible

  4. Beginning from Cisco IOS XE 17.18.1, then xFSU will automatically abort if the FPGA version is not supported.

     You can also use the show xfsu eligibility command to check if the FPGA version is compatible.

• This feature is supported only if the device is running in install mode.

• This feature is not supported on a device that is configured with Spanning Tree Protocol (STP) only. The device must additionally be configured with either Rapid Spanning Tree Protocol (RSTP) or Multiple Spanning Tree Protocol (MSTP).

• For a root device, Extended Fast Software Upgrade is not supported if any of the device ports in forwarding state are connected to a STP peer (A device with STP configured and directly connected to root device)

• For a device, with STP configured and not defined as a root device, Extended Fast Software Upgrade is supported only if the number of device ports in the forwarding state connected to a STP peer is less or equal to 1.

The following restrictions are applicable for a stacked device:

• This feature is not supported if the device stack is configured in the partial-ring state.

• This feature is not supported on a device that is configured with Bidirectional Forwarding Detection (BFD).

• This feature is not supported on a device that is configured with MACsec Key Agreement (MKA).

• This feature is not supported on a device that is configured with Cisco TrustSec.

• Configured UniDirectional Link Detection (UDLD) message intervals are ignored during traffic downtime. The intervals are restored to the configured values after Extended Fast Software Upgrade is completed.

The following restriction is applicable for a standalone device:

For all protocols other than the following, the traffic downtime will be longer than 30 seconds:

• Layer 2 Switching

• Per VLAN Spanning Tree (PVST)

• STP with RSTP or MSTP

• Static Port-channels (Mode on)

• UDLD

• Virtual routing and forwarding (VRF)

• Open Shortest Path First (OSPF) or OSPFv2 or OSPFv3

• BGP (IPv4 and IPv6 address families)

• IS-IS

• Flexible NetFlow

• QoS

• Link Aggregation Control Protocol (LACP)

• IEEE 802.1X Port-Based Authentication

• MAC authentication bypass

• Web authentication

• Internet Group Management Protocol (IGMP) snooping

• Multicast Listener Discovery (MLD) snooping

This table provides release and related information for features explained in this module.

These features are available on all releases subsequent to the one they were introduced in, unless noted otherwise.