To upgrade Moodle 4.2.5 to Moodle 5.0.1, follow this structured process, which aligns with Moodle’s official documentation and best practices1234:

1. Check Server & Software Requirements

• Supported Upgrade Path: You can upgrade directly from 4.2.5 to 5.0.1 (Moodle 5.0 only supports upgrades from 4.2.3 or later)12.
• PHP: Minimum 8.2.0 (64-bit only). PHP 8.3.x/8.4.x also supported.
• Database: PostgreSQL 14+, MySQL 8.4+, MariaDB 10.11.0+, SQL Server 2017+. Oracle is not supported in Moodle 5.0+.
• PHP Extensions: sodium is required.
• PHP Setting: max_input_vars must be ≥ 5000.
• Database Prefix: Must not exceed 10 characters.
• In Moodle, go to Site administration > Server > Environment and check for any warnings or errors for Moodle 5.013.

2. Preparation & Backup

• Test the upgrade on a copy of your production site first13.
• Backup these three areas:
  • Moodle software files (your Moodle directory)
  • Moodle data directory (usually moodledata)
  • Moodle database (full SQL dump)134

3. Check Plugins

• Visit Site administration > Plugins > Plugins overview.
• Update all plugins and themes to versions compatible with Moodle 5.01.
• If a plugin is not compatible, remove its code (do not uninstall via the UI, to preserve data), or update it1.

4. Enable Maintenance Mode

• Go to Site administration > Server > Maintenance mode and enable it14.

5. Replace Moodle Code

1. Download Moodle 5.0.1 from the [official Moodle download page]4.
2. Upload the new Moodle package to your server.
3. Create a backup of your current Moodle code (e.g., move everything in your Moodle directory to a new folder like OLDSITE)4.
4. Extract the new Moodle code into your Moodle directory4.
5. Copy config.php from OLDSITE to the new Moodle directory4.
6. Copy any custom plugins/themes (ensure they are compatible).
7. Do not overwrite the moodledata directory.

6. Start the Upgrade Process

• Web Interface: Open your Moodle site in a browser. The upgrade will start automatically—follow on-screen instructions134.
• Command Line (recommended for large sites): bashphp admin/cli/upgrade.php
• The process will check plugins and update the database schema15.

7. Post-Upgrade Steps

• Complete the upgrade: Ensure all steps show “success” and resolve any plugin issues15.
• Disable maintenance mode.
• Test your site: Check user logins, course access, file uploads, and plugin functionality.
• Review logs for errors.

8. Cleanup

• Once satisfied, you may delete the backup of your old Moodle code (OLDSITE). Keep your database and data directory backups for a while4.

Upgrade Steps Summary Table

Important Notes

• Never skip backups.
• Test the upgrade on a staging copy first.
• Check plugin compatibility before upgrading.
• Do not use Oracle Database—unsupported in Moodle 5.0+.
• Upgrade may take significant time for large sites—plan accordingly.

For full details, consult the [Moodle Upgrading documentation]13.

References:
1: Moodle Upgrading Guide
2: Moodle 5.0 Release Notes
3: Upgrade Overview
4: Tech Fry: How to Upgrade Moodle

1. https://docs.moodle.org/en/Upgrading
2. https://moodledev.io/general/releases/5.0
3. https://docs.moodle.org/en/Upgrade_overview
4. https://www.techfry.com/moodle/how-to-upgrade-moodle
5. https://www.youtube.com/watch?v=eGzlGvCyXVA
6. https://docs.moodle.org/en/Upgrading_FAQ
7. https://www.idslogic.com/blog/moodle-5-0-release-features-enhancements-lms-upgrade
8. https://mindfieldconsulting.com/how-to-upgrade-moodle-from-2-0-and-2-x-to-latest-version/
9. https://www.youtube.com/watch?v=0ejRODDEHJg
10. https://www.youtube.com/watch?v=aSoW-Jd3xqs