Debug & Update Web App - Based on PHP, Smarty PHP, Ajax, JavaScript, MariaDB, API -- 2

Hi, We have a web app for internal project management, the job of this app is to manage our companies projects, and for the same it includes User Management, User Documents Management, Hours dediced to a project, billing of those hours, all the reporting of progress, and then finally posting and fetching data from QuickBooks API. We require a freelancer who can work continuously with us firstly to debug the app, and then provide new features and then to maintain it.