As a seasoned full-stack developer with over 10+ years of experience in website development, specifically with extensive knowledge of Laravel, MySQL, and PHP, I believe my skills make me an ideal candidate for this project. Not only have I successfully undertaken similar projects in the past, but my advanced competencies in upgradation, UI/UX redesigning, backend optimization, testing/debugging, and data migration align perfectly with your requirements.
Moreover, my strong background in computer science and healthcare IT - particularly working with LIMS and Mirth Connect - gives me an edge in understanding complex systems like yours. Being adept at both frontend and backend technologies forte including React, Vue, Angular - HTML5/CSS3/JavaScript/jQuery on the frontend and Node/Express/PHP/Laravel/CodeIgniter/Django on the backend - I can deliver efficient solutions for both modernizing your SaaS application's UI design and enhancing its performance to accomodate scaling.
Additionally, I'm well-versed in database management, including MySQL (your current system), MongoDB, SQLite, PostgreSQL - ensuring smooth data migration without any loss or corruption. My familiarity with AWS deployment and Linux System Administration augments my capacity to handle final deployment seamlessly. Consider me as an investment that will guarantee an improved and secured SaaS application that stands the test of time.