Prusa notification 13802 (New Firmware Available) appears on the MK4 and its equivalents are #31802 on the CORE One, #35802 on the CORE One L, #26802 on the MK4S, #27802 on the MK3.9S, #21802 on the MK3.9, #28802 on the MK3.5S, #23802 on the MK3.5, #17802 on the XL, and #12802 on the MINI. The printer detected via its Prusa Connect connection that a newer firmware version is available for download.

What the Error Means

This is an informational notice rather than an error — the printer is healthy and functioning normally. The notification appears when the printer polls Prusa Connect and finds that the firmware version installed is older than the latest release. Prusa regularly releases firmware updates that improve print quality, add features such as Input Shaper improvements, fix bugs, and update the bundled ESP32 Wi-Fi firmware. Staying current is recommended but not mandatory; printers continue to operate on older firmware versions.

Step-by-Step Fix

1. Download the latest firmware .bbf file for your model. Go to prusa3d.com/drivers, select your exact printer model, and download the firmware. Confirm the filename matches your model variant (MK4, MK4S, MK3.9, CORE One, etc.).
2. Copy the firmware file to the root of a FAT32-formatted USB drive. Place the .bbf file in the top level of the drive, not inside any folder. Ensure the drive is 32 GB or smaller for best compatibility.
3. Install via USB. Insert the USB drive and navigate to LCD Menu → Settings → System → FW Update, or power the printer on with the USB drive inserted — the printer will typically detect the file and offer to update automatically.
4. Use OTA update if available and connected to Prusa Connect. Some firmware versions support over-the-air updates through the Prusa Connect web interface, which eliminates the need for a USB drive.
5. Do not power off during the update. Wait for the update to fully complete and the printer to restart. The update process takes approximately 2–5 minutes.
6. Confirm the new version number on the LCD after update. Navigate to Settings → Info and verify the firmware version matches what you installed.

Parts Required

• No replacement parts are required for this fix — this is a software update
• USB flash drive (FAT32, 32 GB or smaller) if installing via USB

Firmware updates are recommended to benefit from the latest features and stability improvements. If the update fails, contact Prusa Support at help.prusa3d.com.

Frequently asked questions

What does Prusa 13802 mean?

Prusa notification 13802 (New Firmware Available) appears on the MK4 and its equivalents are #31802 on the CORE One, #35802 on the CORE One L, #26802 on the MK4S, #27802 on the MK3.9S, #21802 on the MK3.9, #28802 on the MK3.5S, #23802 on the MK3.5, #17802 on the XL, and #12802 on the MINI. The printer detected via its Prusa Connect connection that a newer firmware version is available for download.

How do I fix Prusa 13802?

Prusa notification 13802 means a newer firmware version is available. Learn how to download the update and install it via USB or OTA to keep your printer current.