How to Update OpenWrt

as I mentioned in another post, I have a pretty old installation of OpenWrt that I once managed to install on a second hand TP Link AC1200. Because it's been doing its job, I more or less forgot about it and was never bothered with installation of updates or other maintenance stuff.
One thing I realized already quite some time ago was that I was no longer able to "normally" ssh unto the box from a recent linux installation, as I was getting the error

Unable to negotiate with port 22: no matching key exchange method found. Their offer: diffie-hellman-group14-sha1,diffie-hellman-group1-sha1,

Some googling and I found out I had to ssh with option


Just sometimes I'm asking myself if it wouldn't be better to do a decent update of the box, only I'm scared of messing and then having to spend days or weeks just to get it back working again. Plus the box is behind another router provided by my ISP, so I hope I'm kind of safe ...

Is there a foolproof way to update to the most recent or at least a more recent stable version? I really don't know much about OpenWrt (virtually nothing to be honest), not even how I managed to set it up back then. Don't even have an idea what version I currently have or how to find out. So any help will be highly appreciated.

Many thanks,


Unless you changed the default settings of your OpenWrt router,
You should be entering

If you can ssh into the box now, the initial splash screen will tell you the version. It'll look something like this:

BusyBox v1.35.0 (2022-04-20 10:37:37 UTC) built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 OpenWrt 22.03.0-rc1, r19302-df622768da

The bottom line of text tells the version of OpenWrt. From there, we can give further guidance.

Ah right, so stupid of it looks like my version is CHAOS CALMER (15.05, r46767)

Many thanks in advance,

Then it would probably be telnet ...


Seems like you're already on it... but please do update :slight_smile: . That version is ancient.

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Right, but my question was how to go about ...

  1. start here: if you can find your router model it means it is supported. also it will tell which version is supported. be careful though, and identify the exact model version, there might be different hardware releases under the same name.
  2. check the forum if there is any problem with your router on a given owrt release, there might be issues. may or may not impacting your use cases.
  3. bear in mind that since your current version there has been released quite a number of new releases which drastically changed your compatibility options. some old low end devices are not anymore supported due to small memory for example.
  4. in general upgrade is quite easy ( search for upgrade): an utility called sysupgrade is used.
  5. there was a recent major change between v19 and v21 (DSA) which significantly changed the network configuration, and while normally sysupgrade can do upgrades by keeping configuration in this case it is not really possible.
  6. also i don't believe you can do one big jump from v15 to latest, so i suggest to backup your configuration (via web interface there is a menu item for it) and use it as cheat sheet, e.g. ISP accounts or special ip address. but otherwise do a vanilla configuration. probably safest would be to upgrade 15->16->17 etc without any customization and only when you reached latest supported you'll do your configuration.

Do you have the LuCI web interface? There is an upgrade page which will accept an upload from your computer. You’ll probably need to update to 17, then 19, and then 22 if supported. Do not keep settings for any of the upgrades.