There are two ways to upgrade the NVR: online upgrade and local upgrade.

The purpose of this document is to describe solutions for NVR local & online upgrade failures or incorrect firmware version detected.

Note: Procedure before you do that, make sure your NVR version is XX.9.0.8 or above, because our NVR has supported online upgrades starting with firmware version XX.9.0.8.



  1. 1. Network Issue
  2. Firmware Version Span Issue
  3. Downgrade limit
  4. Firmware version mismatch
  5. Other Issue


1. Network Issue

You need to make sure your local network is normal before upgrading online. Generally, the success of an online upgrade depends on your current local network status. If the network is normal, you just need to click “Check”, after the latest firmware version is checked, then click “Upgrade”. If the network is abnormal, you need to adjust your network (check your router, etc.) until it works fine. 

Note: If you are accessing the NVR remotely via DDNS, public IP or VPN, it is recommended to try to upgrade the NVR in a local LAN environment. Otherwise, the upgrade may fail because the version image download times out.


There are two ways to check the current state of the network:

① You can confirm the current network status by ping on your NVR.

NVR network test Path:

Status -> Network Status -> Network Test -> Input “” -> Start

② You can confirm the current network status by ping on your computer. 

Input “ping -t” in the CMD command box to check the packet loss and receive rate of the current network. After a period of time use the shortcut “Ctrl+C” to end the ping. The response time (time field) of the ping command ranges from several millimeters to several hundred millimeters. Generally speaking, a shorter response time indicates a faster network speed. If the response time is long and packet loss occurs, the network is unstable.

Network normal:

Network abnormal or unstable:

Note: Make sure your computer and your NVR are on the same LAN, especially with configuration such as subnet mask and gateway.

2.Firmware Version Span Issue

If the network is running properly, the upgrade may fail because there is a large span between the firmware version to be upgraded and the current firmware version.

For example, if your current firmware version is XX.9.0.9 and the latest firmware version is XX.9.0.18, the online upgrade and local upgrade may fail because the upgrade span is too long.

And if your current firmware version is XX.9.0.17 and the latest firmware version detected by the online upgrade is XX.9.0.18, you can generally upgrade directly.


If the upgrade fails because the span is too large, you can solve the problem by gradually upgrading locally. 

For example, if your current firmware version is XX.9.0.9 and the latest firmware version is XX.9.0.18, you can try to upgrade to XX.9.0.13 first, and then upgrade to XX.9.0.15, finally to XX.9.0.18.

You can contact us ( and ask about the upgraded firmware version.

Local upgrade path:

Settings -> System ->Maintenance ->Local Upgrade

3.Downgrade Limit

NVR added downgrade restrictions starting with version XX.9.0.16. If the NVR is shipped with firmware version XX.9.0.16 or above, and you want to downgrade to a version before XX.9.0.16, the downgrade will fail due to the downgrade limit. As shown below:

Note: For security reasons, the downgrade version is not recommended, but if this is important to you and you encounter a downgrade failure during the downgrade process, you can contact us ( for help.

4.Firmware version mismatch

Before local upgrade, make sure that the firmware version you download matches your current NVR. If it does not match, the upgrade will fail. You can download NVR version in our website:

For example, if your current NVR firmware version is, but the firmware version what you download is and use it to upgrade this NVR, this will cause the upgrade to fail. As shown below:

5.Other Issue

If any of the following situations occur, you can contact Milesight support by sending an email to Please be sure to explain your problems and attach screenshots and videos of the problems in the email, so that we can better understand and solve the problems for you quickly.

  • Click "Check" on the online upgrade page, and the wrong firmware version appears. Take the camera for example, as shown below:

2.During the online upgrade, the following message is displayed: Firmware file is too large.

3.The online upgrade cannot detect the latest firmware version of the official website. Most likely because the official website and the online firmware version are not synchronized yet, you can download the latest firmware version from our official website and do the local upgrade first. If you really need to know when the online upgrade can be synchronized with the latest firmware version of the official website, please contact us.

You can download the latest firmware version from our website:

4. If your current NVR version is below XX.9.0.8, then you can only upgrade locally, the current version does not support online upgrade.


If your current firmware version is too old, for example, your current firmware version is XX.7.0.XX or XX.8.0.XX, if there is no reason to upgrade, we do not recommend you to upgrade, because they already belong to the old firmware version, we do not continue to maintain at present, if the upgrade failure leads to other problems, it is difficult for us to help you solve.

In addition, we carried out a major product upgrade in November 2018. Due to the instability of the old file system, we fully upgraded to the new file system in November 2018, which has belonged to the new file system since firmware version XX.9.0.1. The stability and retrieval speed of the new file system are greatly improved after the upgrade. The only drawback is that it is incompatible with the old file system. After the old file system firmware version is upgraded to the new file system firmware version, the disk must be formatted before it can be used properly. Therefore, to prevent data loss on your hard disk, we do not recommend you upgrade.