Custom user profile field type for Moodle that validates the Turkish Identification Number (TCKN) using official checksum rules.

• Moodle 4.4 or later
• PHP 8.1 or later

• 11-digit numeric validation
• Cannot start with 0
• Validates 10th and 11th checksum digits
• Works on:
  • User profile edit
  • Signup form
  • CSV user upload

1. Copy the plugin to: user/profile/field/tckn
2. Visit: Site administration → Notifications
3. Create the field: Site administration → Users → Accounts → User profile fields

Select Turkish ID Number (TCKN) as the field type.

Recommended settings:

• Short name: tckn
• Visibility: Not visible to other users
• Lock field if users should not edit it

This plugin does not create its own database tables. Field values are stored in Moodle core user profile tables.

GNU GPL v3 or later.