The process of replacing the ShadowSnap client on your server would require to use a third party tool to uninstall ShadowSnap and make sure that all leftovers are cleared. Then, you would have to reboot the machine two times, after uninstalling the client and after installing the new one. Please schedule this accordingly. 

1. To uninstall the client, use Revo Uninstaller to clear all leftovers from the application. Download the application from this link: https://www.revouninstaller.com/download-free-portable.php
2. Once downloaded, find the file and launch it.
3. On the list of applications, you have to search for ShadowSnap and StorageCraft software. 
4. Start uninstalling ShadowSnap first, by right clicking on it and choose Uninstall. 
5. After the process completes, over the Uninstalling ShadowSnap windows from Revo, check Scanning Modes Moderate and click on Scan. 
6. If Revo shows any leftovers in the registry click on the Select All button, and then on Delete. You’ll be prompted to confirm if you want to proceed, so click on Yes, and then on Finish.
7. The next step is to remove StorageCraft application. Right click on it and choose Uninstall. 
8. After the process completes, you’ll be prompted if you want to restart the computer. You still have one step left before doing this, so choose No, I will restart my computer later and hit on Finish.
9. Over the Uninstalling ShadowSnap windows from Revo, check Scanning Modes Advanced and click on Scan. 
10. If Revo shows any leftovers in the registry click on the Select All button, and then on Delete. You’ll be prompted to confirm if you want to proceed, so click on Yes, and then on Finish.
11. Once this is completed, please proceed to reboot the server the first time.
12. Once the machine comes back up, install the Datto Windows Agent from this link: https://www.datto.com/downloads/DattoWindowsAgent.exe. 
13. Reboot the server one last time. 
14. Then go to the Datto web Portal and click on the Protect tab.
15. From there find the server you’re working with and click on Remove Agent on the left side. 
16. Once it completely disappears from the Protect tab list, click on the Add a New Agent button on the top upper corner. 
17. Choose Agent Based System. 
18. Enter the IP address of the machine where you installed the client. 
19. For the option, Do you want to create this agent based on a template or another agent?, choose Yes, please. Then Select a Template or agent from the dropdown. You can choose any of the servers you have already added to copy the settings it has, like scheduling, retention, screenshot verification schedule, etc. 
20. For the option, Do you want to encrypt your backups?, select Yes, please. Then enter a Passphrase. This password should be the same you have been using to add the other servers to the Datto, so it won’t be confusing to remember it. You have to save this password securely because we cannot recover it, and if you lose it we would have to delete the data and re-pair the agent again. 
21. Wait until the pairing process completes.
22. After that, you'll be redirected to the Protect tab and from there you can Start a Backup.