What is MIDI 2.0? UMP, 32-bit and MIDI-CI explained

MIDI has been around since the eighties, and MIDI 1.0 still works today. But it reaches its limits when it comes to precisely controlling modern software instruments. MIDI 2.0 closes those gaps. Here's what's behind it and why KnobShift is built on it from end to end.

What is MIDI 2.0?#

MIDI 2.0 is the next generation of the MIDI standard, introduced in 2020. Its key additions are:

• a new message format, the Universal MIDI Packet (UMP),
• much higher resolution for values such as velocity and controllers,
• MIDI-CI (Capability Inquiry), which lets devices talk to each other.

MIDI 2.0 is designed to be compatible with MIDI 1.0. UMP can carry MIDI 1.0 messages too.

What is the Universal MIDI Packet (UMP)?#

MIDI 1.0 sends a continuous stream of individual bytes. UMP instead packs messages into fixed packets made of 32-bit words, 32, 64, 96 or 128 bits long depending on the message. That has several advantages:

• There's room for high-resolution values.
• Instead of 16 channels, there are 16 groups of 16 channels each.
• The same format works across different transports, such as USB or a network.

7-bit vs. 32-bit: why does resolution matter?#

A classic control change value in MIDI 1.0 has 7 bits, which means only 128 steps from 0 to 127. On a volume control you barely notice. But if you slowly turn a filter's cutoff, individual steps can become audible, often called “zipper” noise.

MIDI 2.0 resolves controllers with 32 bits. That's over four billion steps. Even very fine, slow movements reach the plugin without steps. MIDI 2.0 also adds Assignable Controllers, with thousands of freely assignable controllers per channel, also at 32 bits.

What is MIDI-CI?#

MIDI-CI stands for Capability Inquiry. It lets two devices find each other and ask what the other one can do. MIDI 1.0 had very little of this: a controller sent values without knowing whether or what arrived at the other end.

Parts of MIDI-CI include:

• Discovery: devices recognize each other.
• Profiles: agreed standard mappings for certain types of devices.
• Property Exchange: exchanging structured data.

What is Property Exchange?#

With Property Exchange, one device can query or set information on another as structured JSON data. One example is the list of all controllers on a channel, including their names (the ChCtrlList resource). A device can also subscribe to changes and then receives new values automatically.

For controlling plugins, this is the key point: you no longer have to map a controller to CC numbers by hand. The other side describes which parameters exist and what they're called.

How does KnobShift use MIDI 2.0?#

KnobShift is built on MIDI 2.0 throughout:

• All messages between iPad and Mac travel as UMP, over a USB cable or over Network MIDI 2.0 on Wi-Fi (USB, Wi-Fi).
• Every plugin parameter is sent as a 32-bit Assignable Controller.
• The iPad app and KnobShift Companion find each other automatically via MIDI-CI.
• Via Property Exchange, the Companion sends the parameters of the plugin currently in focus to the iPad. The app builds its interface from them automatically, sorted into sections such as oscillators, filters and envelopes.
• Values, display text, focus changes, bypass and touching a control for touch automation also run over Property Exchange.

Because the connection works in both directions, the controls on the iPad move along when you play back automation in your DAW. More in Record automation with KnobShift.

Do you need MIDI 2.0 hardware?#

Not for KnobShift. You need a Mac running macOS 14 or later, an iPad with the KnobShift app and, for Wi-Fi, macOS 26.4 or later. To get started, see Install KnobShift on your Mac. You can ask questions about MIDI 2.0 and KnobShift in the forum.