Back up FIRST!

Base on your OS, locate your wallet.dat. This file contains your private key information so please back up this file before proceeding.

For Windows, the default directory is located at
%APPDATA%\Syscoin
or
C:\Users\YourUserName\Appdata\Roaming\Syscoin

For Linux, the default directory is located at
~/.syscoin

For MacOS, the default directory is located at
~/Library/Application Support/Syscoin

Copy the wallet.dat to somewhere safe

Linux + MacOS

On Linux and MacOS, you can choose to use the pre-built binary or build from source code:
https://github.com/syscoin/syscoin/releases

Compiling from source code

If you ran 4.0.3 before, please do the following first before checking out the latest code:
https://github.com/syscoin/syscoin/releases

cd ~/syscoin
git checkout v4.0.3
sudo make uninstall
make clean

This uninstall the 4.0.3 binaries from /usr/local/bin and then clean up the repo
Proceed as usual after

git checkout v4.1.0
./autogen.sh
./configure
make
sudo make install

Windows

On Windows, please download the latest version here: https://github.com/syscoin/syscoin/releases

If you prefer an installer, use "win64-setup"
If you prefer a zipped standalone version, use "win64zip"
If you previously used the installer for installing 4.0.3, you'll need to uninstall 4.0.3 first.
If you can't locate the uninstaller, go to Settings -> Apps & Features and locate Syscoin Core and click on Uninstall.
The uninstallation process will remove previous software, not your wallet data.

After Syscoin 4.0.x is uninstalled, please proceed to installing 4.1.0 normally.

Masternodes

Masternode Install/upgrade guide can be found here:
https://github.com/syscoin/Masternode-Install-Script

Troubleshooting

geth_sync_status stuck

If getblockchaininfo shows that geth_sync_status stuck at waiting, check if the following processes are running:

sysgeth.nod
sysrelayer.nod

If sysrelayer.nod is not running, please find the installed location for Syscoin Core
default path is as the following
Windows: C:\Program Files\Syscoin
MacOS: /Applications/Syscoin-Qt.app/Contents/MacOS/
Linux: /usr/local/bin
Check if a file named scrypt.node exists. If yes, remove this file and restart Syscoin

If sysrelayer.nod is running, please give Geth some times to sync (~30 minutes). If it's still not synced, please delete the geth data directory and try again. The default path is at the following:
Windows: %appdata%\Syscoin\geth
MacOS: ~/Library/Application Support/Syscoin/geth
Linux: ~/.syscoin/geth

Blocks not syncing due to no peer

If the block is not syncing, and you see an empty peer list, please launch the console and enter the following command:
addnode 52.203.169.241 onetry