Firmware v2.1.13

danngreen · April 6, 2026, 8:45pm

Firmware v2.1.13 is out and has two much requested features:

New Features

Support summed inputs jacks (multiple outs connected to a single input). All cases of panel mappings and virtual cables being summed to a single jack should work. Patches created in VCV Rack that use this feature should work seamlessly when played on the MM, and the MM firmware allows you to patch multiple outputs to the same input. This method of patching is more efficient than using mixers if you just want simple unity mixing.
Midi CC control of active Knob Set. This can be enabled in Settings > Preferences > MIDI. Sending a CC value 0-7 on the chosen MIDI Channel and CC# will immediately switch the Knob Set to the 1st - 8th (CC value 0=>1st, 1=>2nd, 2=>3rd, etc…).

Fixes/Improvements

Made MMAIO connection more robust by automatically resetting the bus if no activity in 5 seconds
In the Knob Set > MIDI page, clicking on a panel MIDI mapping would crash, and MIDI mappings to Expander jacks displayed “??”. Fixed.

Edit (forgot to mention):
For the summed inputs feature, this will work with any version of the 4ms VCV Rack plugin. Except if you patch multiple cables to a Hub “Out” jack, then you need to use v2.1.8 for the hub jack to output the sum of both virtual cables. This will be submitted shortly to the VCV Library, in the mean time download it here: Release Development Build: vcv-v2.1.8 · 4ms/4ms-vcv · GitHub

gabrielroth · April 6, 2026, 9:44pm

Excited for summed inputs! A great quality-of-life feature.

offthesky · April 7, 2026, 3:08am

thanks a huge for summed inputs! definitely opens things up for more efficient patching

BobH · April 7, 2026, 3:24am

@danngreen check the related expander bug topic, no MIDI outputs at all now (no crash though).

danngreen · April 7, 2026, 8:51pm

Ok fixed!
See Firmware v2.1.14

Holofonze · April 7, 2026, 8:58pm

Question. Can the new active knob set control be mapped to the different buttons on the buttons expander? I have been thinking of getting one, and this feature alone would make it well worth it imo.

danngreen · April 7, 2026, 9:18pm

Not yet, but we just came up with a way to do it easily

Holofonze · April 7, 2026, 9:33pm

Ah okay, so in a future update the buttons will be able to change knob sets?

danngreen · April 7, 2026, 10:15pm

Yep, probably the next release.
The idea is to play on the existing UI of how you can change knobsets by pressing the Back button and turning the encoder. The feature would be to hold down the Back button and a press button on a Button Expander, and it’ll jump to that knob set.

Holofonze · April 7, 2026, 11:03pm

Nice! Will you also include a way to map the buttons to different knob sets, but not have to hold down the back button to select them?

danngreen · April 8, 2026, 5:01am

Considering adding an option for dedicating a button expander as a knob set navigator. But you would have to sacrifice a button expander to do that. That is, you couldn’t use the button expander for mappings in some patches, and for knobset changes in other patches (unless you don’t mind going back to the preferences page to enable/disable the feature).

Holofonze · April 8, 2026, 5:44am

It’ll definitely be a useful option for larger patches with multiple knob sets, even if it gives up the use of buttons for normal use.

danngreen · April 10, 2026, 4:58am

OK, I implemented this, and it seems to be working with both the Back + Expander Button mode, and for just directly changing knob sets with each expander button press. There’s a PR open for it, so if it passes all tests it might be in the next release:

github.com/4ms/metamodule

MetaButton Expander can select knobset (#566)

main ← button-exp-select-knobset

opened 04:56AM - 10 Apr 26 UTC

danngreen

+227 -16

This PR adds MetaButtons expander support for changing the knob set. A new pr…eference controls the behavior: - Disabled - Specific expander (1–4) — one designated expander changes knob sets. - Any/All expanders — any MetaButtons expander can change knob sets. An optional Back + Expander Button mode requires holding Back while pressing an expander button to switch knob sets, mirroring the existing Back + Encoder turn behavior. Back events are suppressed on button release when this mode is active. When enabled, Button 1 jumps to knob set 1, Button 2 to knob set 2, etc. If the patch doesn't have the requested knob set, the button acts normally (i.e. it passes the pressed/released events to the module it's mapped to). Notes: Regardless of feature state, holding Back now suppresses all MetaButtons events in the Audio Stream (i.e. modules will not see button events while the Back button is held down). Mapping buttons for both normal use and knob set navigation is not recommended when Back + Expander Button is disabled — button events may fire against either the old or new knob set mappings unpredictably. Enable Back + Expander Button mode to avoid this if you intend to use button mappings AND button knob set navigation in the same patch. This adds support for the MetaButtons button expander to jump to a knob set. It adds a preference in the settings to disable the feature, or choose a MetaButtons expander to change knobsets (1-4), or let any/all MetaButtons to change knobsets. There is also an option to only change the knobset when an expander button is pressed while the Back button is held down. This mimics the behavior of Back + Encoder to change knobsets, and will block any "Back" events when the buttons are released. When enabled, pressing button 1 will jump to knobset 1. Button 2 will jump to knobset 2, etc. If the current patch does not have the requested knobset, then the button will act normally. In all cases, whether or not the Button Expander Selects Knob Set feature is enabled or disabled, whenever the Back button is held down all events from the MetaButtons are ignored by the AudioStream. This was done to minimize the load on the audio stream while avoiding conflicts and race conditions if the user wants to use the buttons for normal maps AND also changing knob sets. If the buttons are used for normal maps and the Back+Expander Button feature is disabled, then it's possible modules will not see all button events, due to race conditions. That is, pressing the button might change the knobset and then send a pressed event based on the new knobset mappings -- or it might send a pressed event based on the previous knobset mappings and then change the knobset. Which one happens is unpredictable. Therefore it is not recommended to map buttons that are also used for changing knobs. If you must do so, then enable the Back+Expander Button feature while will avoid weird behavior.