The IPMI or BMC is the Remote Management Interface, which you can use to maintain the system remotely. Additionally, useful information about the hardware configuration, temperatures of the components, and serial numbers can be read out via IPMI. The IPMI also has firmware that can require updates like the BIOS, almost all Supermicro servers have an IPMI.
As with the BIOS update, as long as there are no security updates or problems with the IPMI, you do not necessarily need to update.
You can get the firmware updates directly from the Supermicro website, simply enter the motherboard or barebone name into the search engine of your choice.
On the download page itself, you will find the release notes of the current version, as well as notes about the flash process.
In some cases, like in the example picture, the download is only possible in a bundle with the BIOS update. In the download, there are 2 .zip folders, one for the BIOS and one for the IPMI update. The BIOS update is described in another article, we only need the .zip folder, which is named like the current version you want to update (173_11 for instance).
Inside this second .zip file is a 32MB .bin file, this file is used for the update.
You can reach the IPMI's WebGUI by entering the IPMI's IP into a web browser that is on the same network as the server's IPMI. You should find yourself at a login prompt that looks something like this.
For newer IPMI WebGUIs, the web interface looks different, but the functionality remains the same.
Unless changed, the default user name is ADMIN . In older IPMI versions, the default password was also ADMIN. That has been changed due to new regulations so that the password is generated randomly for each system. The password is either a label on the system or the mainboard. In our Mac address emails, we also send the IPMI passwords, so if you can't find the password, you are also welcome to contact us with the order number of the system.
As soon as you have logged in, please select "Maintenance -> Firmware Update" by clicking on the tab.
There, please click on enter "Firmware Update Mode". During the Firmware Update, no other actions can be performed on the IPMI.
In the next menu, the .bin file mentioned earlier must be uploaded via Windows Explorer. 
As soon as the file is uploaded, you will reach the last menu before the flash is started. Here, settings and, among other things, the SSL certificate can still be retained. For a complete flash, however, Supermicro recommends that all items are deselected, except for the SSL certificate. As long as none have been installed, this point can be ignored anyway.
IP configurations are not affected, IP settings are not reset after an update in this way.
Now the update will start, once the update finishes, the BMC/IPMI will restart. After a short waiting time, you are back in the login interface. After a new login, the updated version can be checked under "Firmware Revision"!