Dear Partner,

The minting and onboarding interface on the Mosaic Blockchain is now live.

We would like to inform you about some important details.

All written and video materials necessary for minting and joining the network can be found on the mosaiconboarding.com website. Here you will also find — under a separate menu — the documentation required to connect to the DEVNET, so that in the future you can test and practice at any time.

It is worth regularly checking the posts uploaded under the Blog menu, as this is where we upload all news and information that are essential for smooth onboarding and validation on the live blockchain, ensuring that you remain fully up to date.

To make the transition to the Mainnet even smoother, in addition to the user guides available on mosaiconboarding.com, we would also like to provide the following information:

Updates:

Updates are executed on Mondays or Tuesdays.
These reach every machine visible in the Explorer (powered on and online) within 24 hours, so by Wednesday you should already encounter the new version.
Therefore, we recommend checking the operation of your node on Wednesdays or Thursdays.

Devnet Testing:

Before using the Mainnet, please gain sufficient experience on the Devnet, which serves the purpose of practice and testing. Due to the properties of blockchain technology, on the Mainnet it is usually impossible to locate or correct user errors, meaning that in certain cases we will no longer be able to help.

Customer Support — info@mosaicchain.io:

From now on, Devnet and Mainnet run simultaneously.
Please help our work by indicating in the subject line whether your message refers to Devnet or Mainnet.
For example:

• Mainnet – minting issue
• Devnet – indexer not syncing

Processing order of incoming emails is always:
Mainnet → Devnet → all other emails

If the subject line does not begin with “Mainnet” or “Devnet”, your email will be moved to the end of the queue.

You will always receive an automatic message confirming receipt, in which you will find the latest version numbers:

• Latest Mainnet version: ……… (verify at ………)
• Latest Devnet version: ……… (verify at ………)

Error Reporting:

When reporting an issue, in addition to a precise description, please attach a photo of the error; otherwise we cannot process your request.
Also, include your wallet address and validator name in your message.

If you reply again on the same topic, please continue the conversation by replying to the previous email so that we can see the entire thread.

Loss of Support:

We remind you again that we do not investigate errors resulting from unsupported configurations.

If you run multiple validator NFTs on a single node device, and one validator uses resources at the expense of another, or if you do not run a physical machine (e.g. cloud service), or use virtual machines as validators, then resolving these issues is — as we have repeatedly stated and as written in the Validator Node Requirements document — your own responsibility.

With appropriate expertise these configurations can work, but our resources are dedicated to supporting node owners who follow the “one node, one validator” and other rules.

New OS:

The Mainnet OS includes all fixes released for Devnet, plus some additional improvements.
Mainnet functions in the same way as Devnet; therefore, if you had no issues on Devnet, you should not encounter issues on Mainnet.

Mining Service:

Using the Mainnet Minting Service (minting NFTs and MOS coins into your Mainnet Subwallet) has no effect on Devnet functionality, so you may perform it anytime.

However, after installing the Validator OS, during the connection process you will need your NFT minted on the Mainnet, so minting beforehand is essential.

Validator OS Download:

When installing the Mainnet Validator OS on your validator machine, all Devnet node data will be erased.
Therefore, you cannot run both Devnet and Mainnet on the same machine simultaneously.
(While an expert could theoretically solve this, we do not recommend it to anyone.)

If you still wish to practice on Devnet, delay Mainnet installation, or use a separate machine.

Once Mainnet is installed on your node, you will still be able to access your Devnet NFTs and TMOS coins via the Devnet Explorer — but you will no longer be able to produce blocks or validate on Devnet, since your Devnet node will not exist.

After installing Mainnet, you must use the Mainnet Explorer, as Devnet Explorer will no longer display Mainnet-related data, which may be misleading.
Please pay attention to whether you click on the Mainnet or Devnet Explorer button at the top right of mosaicchain.io.

As the Mainnet onboarding progresses, the number of validators on Devnet will decrease. Depending on how users proceed (e.g. not chilling as requested), Devnet Explorer may display unusual activity (elevated faulted or unhealthy nodes, etc.).

Recommended Steps for Joining:

1. First, carefully consider when to make the transition.
2. Then mint your NFTs to the Mainnet. (Duplicate your seed phrase multiple times and store it securely!)
3. Read and watch all written and video materials in the user manuals, and follow the described processes during onboarding.
4. Install the Mainnet version of the validator OS (available from 18 November 2025, 10:00).

Using Devnet:

If you encounter an issue on Devnet, always check first whether you are running the latest version.
The Mainnet Validator OS naturally contains the latest version.

Checking the Devnet Version on Your Machine:

1. Click the Validator Dashboard button at the top right of the Explorer.

5. Select the name of your node, enter your username and password, then log in.
6. Check whether the “Mosaic Stack” version under Installed Packages shows 1.0.1.
7. If yes, you have received the update; verify your node operates correctly.
8. Please always notify us whether the issue is resolved — even if everything works properly.

If you do not see version 1.0.1, the update did not install automatically.
In this case, you can install it manually as described below.

Manual Update Installation:

Only perform the steps below if you do not see the latest version number.

Start with Option I, and only proceed to the next option if the update is unsuccessful.

I. Option — Update via Validator Dashboard:

1. Visit the Validator Dashboard:
   https://devnet-explorer.mosaicchain.io/sign-in

9. Select your validator, enter your username and password, then click Continue.
10. In the top-right corner of the Installed Packages panel, click the refresh icon with arrows to update the Mosaic Stack manually.
11. Wait 5–10 minutes, then reload the page; verify that version 1.0.1 appears.
12. If yes, the update installed successfully. Ensure your machine is in Active state (if not, click Unchill), then check for proper operation.
13. If the version is not 1.0.1, proceed to Option II.

II. Option — Update Directly on the Validator Machine (via command):

1. Connect a monitor and keyboard to your validator machine.

14. Power it on if it is not already running.
15. Log in to the validator machine as follows:

• When the login prompt appears, enter the username you assigned during installation, then press Enter.
• When prompted for the password, type it even though no characters appear (for security reasons), then press Enter.

16. After successfully logging in, type the following command exactly as it appears below. It cannot begin with a space and cannot end with a space, but you must type a space after the word “sudo”! After you type the command, you can press Enter to tell the computer that you are finished typing so that it can execute the command.

The command you should type is as follows:
sudo /opt/mosaic/update-mosaic.sh

17. Press Enter. Wait 5–10 minutes. The node will then reappear in the Devnet Explorer. (https://devnet-explorer.mosaicchain.io/).
18. Return to the Validator Dashboard, log in, and check whether version 1.0.1 appears under Installed Packages.

• If yes, verify that your machine is Active and operating correctly.
• If not, proceed to Option III.

III. Option — Update with Chain Service Temporarily Stopped

1. Log in to the validator machine (if not already logged in).
2. After successfully logging in, type the following command exactly as it appears below! It cannot begin with a space or end with a space, but you must type a space after the word “sudo”. After you type the command, you can press Enter to tell the computer that you are finished typing so that it can execute the command. The commands you need to type are as follows (press Enter at the end of each line):
   sudo systemctl stop mosaic-chain-devnet.service

sudo /opt/mosaic/update-mosaic.sh

sudo ntpd -s

sudo systemctl start mosaic-chain-devnet.service

20. Wait 5–10 minutes; your node will reappear in the Devnet Explorer.  (https://devnet-explorer.mosaicchain.io/).
    
21. Go to the Validator Dashboard, log in, and check the “Installed Packages” box to see if you see Mosaic Stack version 1.0.1!

• If so, the update was installed successfully. Make sure your machine is in “Active” status (if not, click the Unchill button), and then check if you experience any malfunctions!
• If you don’t see version 1.0.1, let us know and we’ll help you move forward!