OpenWrt 21.02.0 first release candidate

Hauke Mehrtens hauke at
Mon Apr 26 22:05:03 BST 2021


The OpenWrt community is proud to announce the first release candidate 
of the upcoming OpenWrt 21.02 stable version series. It incorporates 
over 5800 commits since branching the previous OpenWrt 19.07 release and 
has been under development for about one and a half year.

WPA3 support included by default

WPA3 was already supported in 19.07 but it was not provided by the 
default set of packages in OpenWrt images.
With 21.02, all packages necessary to provide WPA3 are installed by 
default in OpenWrt images.

TLS and HTTPS support included by default

TLS support is now provided by default in OpenWrt images including the 
trusted CA certificates from Mozilla. It means that wget and opkg now 
support fetching resources over HTTPS out-of-the-box. The opkg download 
server is accessed through HTTPS by default. OpenWrt switched from mbed 
TLS to wolfSSL as the default SSL library, mbed TLS and OpenSSL are 
still available and can be installed manually.

Initial DSA support

DSA stands for Distributed Switch Architecture and is the Linux standard 
to deal with configurable Ethernet switches.
OpenWrt 21.02 comes with initial support for DSA, which replaces the 
swconfig system that OpenWrt was using up until now. Not all targets 
have been ported: some devices still use swconfig while some devices 
already switched to DSA.
This is a significant change to how switch ports and VLANs are managed. 
As such, sysupgrade will not be able to convert existing swconfig 
configuration to DSA configuration (see “Upgrading” below).

The following targets are using a switch managed with DSA in OpenWrt 21.02:
* ath79 (only TP-Link TL-WR941ND)
* bcm4908
* gemini
* kirkwood
* mediatek (most boards)
* mvebu
* octeon
* ramips/mt7621
* realtek

Increased minimum hardware requirements: 8 MB flash, 64 MB RAM

Due to new features being introduced and the general size increase of 
the Linux kernel, devices now need at least 8 MB of flash and 64 MB of 
RAM to run a default build of OpenWrt.
It is still possible to build custom OpenWrt images (e.g. using the 
ImageBuilder) that may fit devices with 4 MB of flash or 32 MB of RAM. 
However, the level of functionality will be reduced and there is no 
guarantee to stability. See OpenWrt on 4/32 devices for more details and 

New hardware targets

A new realtek target has been added, which is often found in managed 
switches. As a result, it is now possible to run OpenWrt on devices with 
a significant number of Ethernet ports. See supported devices for realtek.
In addition, new bcm4908 and rockchip targets have been added.
Support for many new boards was added to the existing targets.

Dropped hardware targets

The ar71xx was deprecated in OpenWrt 19.07 and was gradually replaced by 
ath79, see ar71xx-ath79 migration. With OpenWrt 21.02, the ar71xx has 
been removed and users must use ath79 instead. If you are still running 
with the ar71xx target, it is recommended to reinstall OpenWrt 21.02 
from scratch. Users already on the ath79 target can use sysupgrade to 
upgrade to OpenWrt 21.02.
Other targets were also removed: cns3xxx, rb532 and samsung.

ASLR activated

Network exposed user space applications are linked as 
position-independent executable (PIE) to allow full Address Space Layout 
Randomization (ASLR) support. This makes it harder for attackers to 
exploit OpenWrt. See Hardening build options for more details.

Kernel with container support

Multiple Linux kernel compile options, needed for Linux Containers (LXC) 
and procd-ujail are activated by default for most targets. This allows 
to use LXC and ujail with the normal release builds.

SELinux support

It is possible to compile OpenWrt with SELinux support. This is 
currently not activated by default.

Core components update

Core components have the following versions in 21.02.0-rc1:
* Updated toolchain:
  * musl libc 1.1.24
  * glibc 2.33
  * gcc 8.4.0
  * binutils 2.35.1
* Updated Linux kernel
  *  5.4.111 for all targets
* Network:
  * hostapd 2020-06-08, dnsmasq 2.84, dropbear 2020.81
  * cfg80211/mac80211 from kernel 5.10.16
  * wireguard backport from upstream Linux kernel
* System userland:
  * busybox 1.33.0

In addition to the listed applications, many others were also updated.

Upgrading to 21.02.0-rc1

Sysupgrade can be used to upgrade a device from 19.07 to 21.02, and 
configuration will be preserved in most cases.

Sysupgrade from 18.06 to 21.02 is not supported.

There is no migration path for targets that switched from swconfig to 
DSA. In that case, sysupgrade will refuse to proceed with an appropriate 
error message:
Image version mismatch. image 1.1 device 1.0 Please wipe config during 
upgrade (force required) or reinstall. Config cannot be migrated from 
swconfig to DSA Image check failed

The default root file system partition size changed for targets/devices 
relying on booting from mass storage (HDD, USB flash, SD card, etc.), so 
MBR will change and any additional partition will be deleted when 

Known issues

* DSA support is new and might not be complete or fully working
* The LuCI web interface has no support for DSA yet
* LuCI writes unnecessary IPv6 RA options to /etc/config/dhcp if the
   user edits interface's DHCP settings. This could prevent client IPv6
  * Update luci-mod-network to git-21.107.58557 or later to fix this

Full release notes and upgrade instructions are available at

In particular, make sure to read the regressions and known issues before 

For a very detailed list of all changes since 19.07, refer to

To download the v21.02.0-rc1 images, navigate to:

- ---

To stay informed of new OpenWrt releases and security advisories, there
are new channels available:

  * a low-volume mailing list for important announcements:

  * a dedicated "announcements" section in the forum:

  * other announcement channels (such as RSS feeds) might be added in the
    future, they will be listed at

As always, a big thank you goes to all our active package maintainers, 
testers, documenters, and supporters.

Have fun!

The OpenWrt Community

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