For Laravel 5.2 support, please look at the 5.2-sup branch in the laravel-firebird repository

https://github.com/jacquestvanzuydam/laravel-firebird/tree/5.2-sup

For Laravel 5.2 support use:

composer require jacquestvanzuydam/laravel-firebird:dev-5.2-sup

Thanks to CyCJIeHok for the changes for Laravel 5.2