Moodle 3.5 → 4.x upgrade, PHP security and ongoing support (part-time, hourly)

We are LangO, a corporate English training company. Our live learning platform runs on Moodle 3.5 on AWS, with a custom theme (theme_lango) and custom plugins (local/lango). It integrates with Cisco Webex and Slack. We build new features with Claude Code. We want a developer who works the same way. We need an experienced Moodle developer for urgent security work, and then part-time support on an hourly basis. URGENT (first 2-4 weeks): - Protect the site against the recent PHP2Shell vulnerabilities: confirm the PHP version, add a web application firewall, check the logs. - Set up a staging site with a sanitised copy of the live database. - Plan, estimate and carry out an upgrade from Moodle 3.5 / PHP 7.2 to a supported Moodle 4.x LTS release and PHP 8.x. - Fix the Webex account selection and token refresh logic (users sometimes cannot join meetings). THEN (about 10-20 hours per month): - Fix access checks on some user pages. - Review and deploy our new feature branches (AI lesson reports, engagement dashboards). - Bug fixes, security updates and small features. REQUIREMENTS: - Proven experience upgrading Moodle 3.x sites with custom plugins to Moodle 4.x. - Strong PHP and MySQL, and Linux server work on AWS (EC2). - Moodle plugin development: database upgrade scripts, scheduled tasks, external API. - Git workflow with branches and pull requests. - Daily use of AI coding tools, ideally Claude Code (or Cursor, Copilot). You will review, test and extend code that we write with Claude Code, and use these tools in your own work. - You review AI-written code critically for security, performance and Moodle standards before it goes live. - Based in Europe, or working in CET hours. Good written English. - Nice to have: Webex REST API, OAuth, Cloudflare. TERMS: Hourly contract with a weekly limit. No fixed fee. We have a written handover document that describes the platform, the open issues and the work done so far. TO APPLY, PLEASE SEND: 1. Your hourly rate. 2. One Moodle upgrade you did: from which version to which, and how many custom plugins. 3. Your availability in the next two weeks. 4. In one sentence: how do you deploy a new database table safely on a live Moodle site? 5. Which AI coding tools do you use every day, and for what? Give one example where you corrected AI-written code. Applications without answers to these questions will not be considered.