# Changes in Release 26.08

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(release-26.08)=
## New Devices

* [Arrcus ArcOS](https://arrcus.com/) containers ([details](build-arcos), [caveats](caveats-arcos)).
* [VPP (FD.io)](https://fd.io/) containers ([details](build-vpp), [caveats](caveats-vpp)) using BIRD or FRR control plane.
* SONiC containers using the community `docker-sonic-vs` image ([details](build-sonic-container), [caveats](caveats-sonic-clab)).

## New Functionality

* The [**routing** module](generic-routing) supports [IPv4/IPv6 access control lists](generic-routing-acl) on Arista EOS and Cisco IOS/IOS XE.
* The new [**services** module](module-services) configures [DNS clients and servers](services-dns-platform): Arista EOS, Cisco IOS/IOS XE, FRR, and Linux nodes can be configured as DNS clients, and a dnsmasq node can act as a DNS server.
* *clab* provider supports the **podman** container runtime ([details](lab-clab)). Use **netlab install podman** to install podman and containerlab, and **netlab test podman** to verify the installation.
* The **linkid** link/interface attribute [uniquely identifies a link or an interface](link-linkid) and can be used to select an endpoint of a tunnel link.

**Minor improvements**

* SR-MPLS Global Block (SRGB) can be configured on Arista EOS, Cisco IOS/IOS XE, and Cisco IOS XR with the **sr.srgb.start** and **sr.srgb.size** parameters.
* [Addressing reports](netlab-report) display interface MTUs.
* Tunnel interfaces use technology-specific names (for example, `gre1` or `wg0`) on FRR, OpenBSD, and Mikrotik RouterOS7.
* Validation tests can use the **ansible** action to collect device state through the device Ansible module ([details](validate)).

(release-26.08-device-features)=
## New Device Features

Arista EOS:
* DNS client
* GRE tunnels (IPv4 transport, transport VRF)
* IPv4/IPv6 ACLs
* Configurable SR-MPLS global block

Bird:
* DNS client

Cisco IOS:
* DNS client
* IPv4/IPv6 ACLs

Cisco IOS/XE:
* Configurable SR-MPLS global block

Cisco IOS/XR:
* Configurable SR-MPLS global block

FRR:
* BFD for IS-IS
* DNS client

Mikrotik RouterOS7:
* GRE and WireGuard tunnels
* Static routes (including VRF, inter-VRF, and discard routes)
* OSPFv3 VRF instances
* IP host mappings

OpenBSD:
* GRE and WireGuard tunnels
* VXLAN (including IPv6 VTEPs)

(release-26.08-device-fixes)=
## Fixes in Device Settings and Configuration Templates

* [Transparent Management _containerlab_ feature] has been enabled for Cisco ASAv, Cisco Catalyst 8000v, Cisco CSR 1000v,  Cisco Nexus OS, Nokia SR-OS (the vrnetlab VM version, not SR-SIM), vJunos router, vJunos switch, vJunos Evolved (vPTX), and Juniper vSRX.

Arista EOS:
* OSPFv2 uses routes learned over GRE tunnel interfaces

Cisco IOSv:
* Use `ip mtu` instead of `mtu` on tunnel interfaces

Extreme EXOS:
* Reject VLAN names that clash with EXOS CLI command names

Junos:
* vJunos router container image bumped to 26.2R1.7

Mikrotik RouterOS7:
* Initial device configuration refactored to use the `extra_initial()` framework
* VLAN configuration no longer fails when VLAN data structures are absent

Nokia SR Linux:
* Container image bumped to release 26.7.1
* Configurable dynamic SRGB label range (**sr.srgb.dyn_start**/**sr.srgb.dyn_size**)

OpenBSD:
* VLAN and initial device configuration use the `extra_initial()` framework

(release-26.08-breaking)=
## Breaking changes

* We enabled the [Transparent Management _containerlab_ feature](https://containerlab.dev/manual/vrnetlab/#management-interface) on vrnetlab-based devices supporting it in July 2026. This change should not impact older containers, but will change the management IPv4 address on virtual machines running in some newly-built containers from 10.0.0.15 (the default management IPv4 address) to the outside (container) management IPv4 address.
* The use of the Transparent Management feature broke some vrnetlab containers that assumed the *containerlab* management network always had an IPv6 subnet. While that's been [fixed in *vrnetlab*](https://github.com/srl-labs/vrnetlab/pull/511), _netlab_ nonetheless configures a default IPv6 management subnet (`fd00:df:1ab::/64`, adjusted on _[multilab](plugin-multilab)_ instances) on the *containerlab* management network to ensure the older containers keep working.
* The default IPv6 management subnet broke the default route on lab hosts without a management VRF (for example, the Linux containers). The Linux container initial configuration script thus disables the RA listener on the management interface (the IPv6 management address is configured by _containerlab_).
* We switched to [sudo-less *containerlab* operation](https://containerlab.dev/install/#sudo-less-operation). If your containerlab-based labs fail to start, check whether your username is in the `clab_admins` group with the `groups` command. To add your username to that group, use:

```
sudo usermod -aG clab_admins $USER
newgrp clab_admins
```

(bug-fixes-26.08)=
## Bug Fixes

* Allocate a unique WireGuard UDP listen port to every tunnel on a node (#3710)
* Do not apply schema defaults to interfaces before the link merge (#3703, #3705)
* Partial `extra_initial()` configurations are deployed correctly (#3670)
* Cisco IOS DHCP client is configured during initial device configuration (#3672)
* Routing protocol configuration is no longer dependent on the DHCP client (#3674)
* Node MTU is not applied to tunnel and loopback interfaces (#3707)
* Cross-provider links no longer destroy tunnel link types (#3649)
* GRE tunnel MTUs are derived from the underlay MTU minus the tunnel overhead (#3747)
* Validation errors show the actual lists instead of 'BoxList' objects (#3719)
* IPv4/IPv6 validators support the 'prefix_or_host' use case and list length validation (#3718, #3722)
* VPP/BIRD OSPFv3 loopback prefix advertisement (#3725, #3729)
* VPP VLAN SVI LCP address synchronization and VLAN MTU (#3730)
* Vagrant default provider is set correctly on WSL (#3673)
* **netlab test** cleanup handles Ctrl-C without crashing (#3720)
* 'show modules' displays the 'dhcp.client.routing' feature flag (#3671)

(doc-fixes-26.08)=
## Documentation Fixes

* Converted device support tables to the new Sphinx **features** directive (BFD, GRE, and WireGuard documentation) (#3736)
* Documented the `docker-sonic-vs` download process and the containerlab workarounds (#3731, #3740)
* Documented the containerlab Transparent Management (CLAB_MGMT_PASSTHROUGH) workaround (#3728)
* Documented the EXOS reserved VLAN names and their source (#3739)