New release candidate: 1.3.7rc1

I’m happy to present you the first release candidate of the 1.3.7 release!

The changelog is once again on the lengthy side again thanks to the maintenance releases now being spread apart a bit further. Don’t let that scare you though 😉

Here are some highlights from the release notes:

  • OctoPrint will now detect prints from SD started through your printer’s built-in controller, if the firmware fulfills a couple of requirements:
    • it must send a “File opened: …” message on start of the print
    • it must respond to an immediately sent M27 with SD printing byte <current>/<total>
    • it must stay responsive during ongoing print to allow for regular M27 polls (or push those automatically) or M25 to pause/cancel the print through OctoPrint. Additionally there’s now support for SD status autoreport capabilities by the firmware.
  • The serial settings got an UI overhaul to be hopefully less overwhelming.
  • The log management has been extracted into its own bundled plugin and now allows log level management. That is especially interesting to quickly get more detailed logs of specific components in case of bug reports and seeking support but can also help tremendously during plugin development.
  • A new bundled plugin “Printer Safety Check” will try to identify printer/printer firmware with known safety issues such as missing thermal runaway protection and display warning if such a printer is detected.
  • OctoPrint now has native support for the following @ commands that can be used in your GCODE files, scripts and basically everywhere where you’d send a command through OctoPrint to the printer: @pause (pauses the print), @resume (resumes the print), @cancel or @abort (cancels the print). More commands can be added through the plugin hooks octoprint.comm.protocol.atcommand.*.
  • GCODE commands sent through the system now have tags attached that can be utilized by plugins to detect the origin of commands (streamed vs file vs GCODE script vs user input vs plugin), the point where it entered the system and so on. A new logger octoprint.util.comm.command_phases was added that when switched to DEBUG will log the lifecycle of the commands through the communication layer including tags to octoprint.log.
  • Disabled plugins now will not only stay deactivated, they won’t even get imported into the system at all anymore to avoid any kind of issues caused by them.
  • And of course there were also quite a number of bugs fixed reported for earlier versions, e.g. auto connect on startup not working if AUTO was set as port, wrong queuing order of cancel script & first line from a printed file on quick start-cancel-start scenarios and incorrect behaviour if a print got cancelled by an error reported from the firmware, plus various fixes of typos and grammar in the documentation.

If you are tracking the “Maintenance RC” release channel, you should soon get an update notification just like you are used to from stable releases.

If you are not interested in helping to test release candidates, just ignore this post, 1.3.7 stable will hit your instance via the usual way once it’s ready 😊

You can find the full changelog and release notes as usual on Github.

Please provide feedback on this RC. For general feedback you can use this ticket on the tracker. The information that everything works fine for you is also valuable feedback 😄 For bug reports please follow “How to file a bug report”.

Depending on how the feedback for this release candidate turns out, I’ll either look into releasing 1.3.7 or fix any observed regressions and push out a new release candidate ASAP.


This is a companion discussion topic for the original entry at

Thanks for all your hard work! I'm going to install it immediately.


Installed, but the printer I usually control is being annoying and so I'm trying to get rid of it... and my MPSM doesn't play nice when I try to auto detect it and I haven't spent the time to debug that. So, about all I can confirm is that it installs fine for me and I can click around. :stuck_out_tongue_winking_eye:

You are fast... I'm still in process of post-release merges and haven't even gotten around to upgrading my own printers :rofl:

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Well when I have no active printers connected to it, there's not much risk in deploying immediately! I clicked through all the settings and everything looked good there. Will try a little harder to get the MPSM connected so I can test some actual prints.

I have it installed too. Works great! Now to finish up my pull request for the plugin repository :smile:

The serial settings were got an UI overhaul to be hopefully less overwhelming.

Something's weird in this wording. Maybe just remove "were"? Perhaps you were originally writing "were overhauled"?

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Yep, indeed I was, thanks. Fixed on the post & here.

Ooh. That's cool. I could use that to determine whether the gcode flavor should be treated as MakerBot (gcode file from their slicer) or RepRap (everything else).

Also, I suspect the SD card print originating at the printer could be done for GPX too. I'll have to see if I can generate the appropriate responses.

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There's not an awful lot of documentation on the tags yet, but the new logger (which can also be enabled and disabled at runtime thanks to @kantlivelong) should hopefully help. Let me now if you are missing something that might be useful!

How do i go about installing the release candidate? i'd be glad to help out testing it.

By switching the release channel to "Maintenance RCs". See here

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Go to settings -> software update -> click the wrench icon

Set Octoprint Version Tracking = Release
Set Octoprint Release Channel = Maintenance RCs

Save, and you should be prompted to update.


Edit - Gina is faster than most


I tried looking at FAQ and seached this forum for "how to install release candidate" but didn't get any hits. Thanks for quick reply :slight_smile:

Yeah, I still have quite a lot of stuff to port over :wink:

You could have found that link on the blog in the post, for some reason the links don't come over here though...

edit The release channel guide is now moved to this very forum:

Well, as I guess was expected the "print started on printer" detection does not work with a prusa because prusa is not sending the "file opened" message.

I created a feature request here:…”-message-on-start-of-the--t15032.htm

I'm not confident enogugh with the 3D printer's firmware to even consider making the changes myself in the code base so I guess that's all at the moment.

On a second note I'm not sure if I'm getting a new error since the update or is it only that I'm paying more attention now to a print started from SD and monitored (or not monitored, whatever) from octoprint but I'm getting the following on octoprint:

State: Offline (Error: Too many consecutive timeouts, printer still connected and alive?)

As stated, maybe it's not an error, maybe the printer is "shutting out" while printing from the SD card.

If it is a new error I can provide logs later or downgrade and try again. I'm printing big files and only have one printer so I can help but with a bit of delay between tests.

Thanks for the update!

I did a test against my own MK3 right when I developed that feature and ran into issues, whereas the Hephestos 2 with stock Marlin performed flawlessly, so yeah, I guess that confirms that. It also seemed like it stopped responding while printing from SD, which might explain your timeouts. Didn't have the time to take a look into the firmware source though to figure out what's happening there.

Thanks for all the hard work Gina! I love OctoPrint so much I just increased my monthly support! Keep up the great work, I'm switching 3 of my 5 (soon to be 6) OctoPrint instances to Maint RC now!

So... How do I install this? I a new to Raspberry Pi. I can install the images but can't see how you install a RC. Do I need to do it manually with Raspian installed 1st????? confused

Easiest way IMO is to use the OctoPi image which simplifies the process, once installed and setup you can change the release channel and update from within OctoPrint. Here is my full Octopi how to video and download links for tools required here: OctoPrint How to Link