How to Identify Shimano Di2 Generations

Types/Generations of Di2

Shimano’s Di2 is divided into compatibility groups according to the “master unit” that manages the Di2 system.

The Di2 master unit is not located in the STI levers or derailleurs, but is built into the battery (or battery mount).

There have been five groups of Shimano Di2 components released so far: the “7970 series” generation, the “BTR/DN100 series” generation, the “DN300 series” generation, the “AUTO SHIFT series,” and the “DN320 series” generation.

Shimano does not officially specify generations for the Di2 system, but for convenience, we will refer to them as generations in the following explanation.

DURA-ACE 7970 Generation

The first-ever Di2 system, DURA-ACE Di2 7970, is a unique setup and incompatible with all modern Di2 parts. Because it has no backward compatibility, we’ve labeled it as Generation 0.

The electric wires used in the 7970 generation are proprietary and not compatible with any other Di2 generation. You must use a full 7970 set for the system to function.

However, the battery unit SM-BTR1 and its charger can still be used with first-generation Di2 systems.

Di2 Generation 1 / BTR Series

First introduced with ULTEGRA Di2 6770, and continued through DURA-ACE Di2 9070 and ULTEGRA Di2 6870, this is commonly referred to as the BTR generation. The generation name comes from the battery model numbers (e.g., SM-BTR2).

• If you’re using an internal battery, the master unit is located inside the battery (SM-BTR2).
• If you’re using an external battery, the master unit is located in the battery mount (SM-BMR1 or SM-BMR2).

Compared to Generation 0, major improvements include:

1. Option for internal battery integration
2. Junction A/B separation, allowing more flexible wiring layouts
3. Support for ANT+ wireless units

The DURA-ACE Di2 R9150, released in 2016, marks the beginning of the DN100 generation (Gen 1.1), but it retains high compatibility with most Gen 1 (BTR) components.

However, there is a key difference in wireless communication:

• BTR generation supports ANT+ only
• DN100 generation supports Bluetooth LE, which is now the standard

So, if you want to use Bluetooth wireless units or a System Information Display, you’ll need to upgrade your master unit to the DN100 series.

Di2 Generation 1.1 / DN100 Series

The “Di2 DN100 series,” introduced with the DURA-ACE Di2 R9150, is a minor upgrade of the Di2 BTR generation. Since most components are compatible with the BTR series, it can be considered a refined version of the first generation.

The master unit is BT-DN110 for the internal battery type, and BM-DN100 for the external battery mount type. Both have model numbers starting with “DN,” making them easy to identify.

The main difference is support for wireless Bluetooth communication.

It’s unlikely that you would downgrade from the DN100 series to the BTR series, but if your setup includes a Bluetooth wireless system, make sure to always use DN100 series batteries when replacing them.

Additionally, the DN100 series master units are compatible with the previous generation BTR series wireless units (ANT+ only).

Di2 Generation 2 / DN300 Series

The second generation of Di2 is the “Di2 DN300 series.” The major advancement is the introduction of the semi-wireless system with DURA-ACE R9200 and ULTEGRA R8100 (rim brake models such as ST-R9200 and ST-R8100 remain wired).

In the DN300 generation, external batteries have been discontinued, and the internal battery “BT-DN300” is the only master unit. While it looks similar to BT-DN110, it has three SD ports, making it distinguishable by appearance.

In the semi-wireless system, only the battery/master unit and front/rear derailleurs are wired, while STI levers act as switches, powered by coin cell batteries.

With Bluetooth built into the rear derailleur, a separate wireless unit is no longer required.

In the Di2 DN300 series, battery charging is done via the connected rear derailleur using the dedicated EW-EC300 charger connector.

For rim brake models, a junction box (EW-JC304) is still needed to connect STI levers to the master unit, as in previous generations.

Di2 2.5th Generation / AUTO SHIFT Series

Released in June 2025, Shimano’s automatic shifting system “AUTO SHIFT” is centered around the “AUTO SHIFT series” Di2 system.

Currently, the AUTO SHIFT system uses only the battery-integrated freehub “FH-U6060” as the master unit, and there is no external battery version. The “FH-U6060” is a system that learns the user’s shifting patterns and performs automatic shifting, but since it learns from manual shifts made with traditional switches, shift switches are required for the learning process.

In the AUTO SHIFT series Di2, the 2nd generation shift switches for road Di2 and the 3rd generation fully wireless switches for MTB Di2 are each compatible.

As for the rear derailleur, there are both wireless (U8050 series) and wired (U6050 series) options depending on the series. For the wired type, you can use DN300 series STI levers and shift switches. Note that even for the wireless (U8050 series), since the rear derailleur itself does not have a battery, the “FH-U6060” is still required as of now.

Additionally, while the AUTO SHIFT series Di2 system appears to be compatible with existing DN300 series Di2 components in terms of parts configuration, as of June 2025, Shimano’s E-TUBE PROJECT compatibility chart only guides usage with the “FH-U6060” as the master unit.

Di2 3rd Generation / DN320 Series

The 3rd generation, Shimano’s first fully wireless “Di2 DN320 series,” made its debut in June 2025 with the release of the XTR M9200 series, DEORE XT M8200 series, and DEORE M6200 series.

Starting from this generation, the rear derailleur is equipped with a removable battery, eliminating the need to install a battery unit inside the frame as was previously required. As for shift switches, since wireless functionality was introduced in the 2nd generation, wireless switches from that generation can also be used with the 3rd generation Di2.

Di2 Generations by Component

Road Di2 Series

The road-oriented Di2 series includes the largest number of product lines and different levels of compatibility, so extra caution is needed when building a Di2 system.

As explained earlier, there are three major generations:

1. 7970 Generation
2. First Generation
3. Second Generation

The First Generation is particularly important to note. Compatibility can vary depending on whether a wireless unit is included. When purchasing a complete Di2-equipped bike or Di2 component set, be sure to check the included battery unit, as this affects the wireless functionality.

Additionally, when assembling a Di2 setup, whether it’s based on the BTR series or DN100 series will determine how the wireless unit is integrated. If you want Bluetooth connectivity, be sure to choose components from the DN100 series.

MTB Di2 Series

Shimano’s MTB Di2 components have expanded their lineup in 2025 with the release of fully wireless Di2 12-speed and CUES’s AUTO SHIFT; however, since there were originally fewer Di2 systems for MTB, it is not as complex as road-oriented Di2.

Just remember that there are three types:

1. MTB Di2 12-speed
2. CUES Di2 11/10-speed
3. MTB Di2 11-speed