How can developers ensure a smooth transition when upgrading WordPress versions?

To ensure a smooth transition when upgrading WordPress versions, developers should first make sure to backup their website files and database. They should also deactivate all plugins and switch to a default theme before initiating the upgrade. After the upgrade is complete, developers should reactivate their plugins and test the website thoroughly to ensure everything is functioning correctly.

// Backup website files and database
// Deactivate all plugins
// Switch to default theme
// Upgrade WordPress version
// Reactivate plugins and test website