Odoo SH Upgrade with Custom Modifications

I'm looking for an experienced Odoo professional to upgrade my Odoo SH from version 15 to 18. This project will involve:

- Retaining all existing custom addons: It's crucial that every custom addon currently in use is preserved during the upgrade.

- Modifying certain custom addons: Some of my existing custom addons will require modifications or updates to ensure compatibility and enhance functionality post-upgrade.

Please, no new custom addons will be added during this process. I simply want to keep things as they are, but improved.

Ideal skills and experience for this job would include:

- Extensive knowledge of Odoo and its architecture.

- Proven experience in upgrading Odoo versions.

- Proficiency in customizing and modifying Odoo addons.

- Excellent problem-solving skills to ensure all custom addons are compatible with the new version.

- Experience in data migration: Ability to seamlessly transfer data from Odoo SH version 15 to 18 without data loss or corruption.