The FDOT Civil 3D 2019 State Kit was released on October 1, 2018. This is the fifth Maintenance
Below is the link for the FDOT2019 Civil 3D State Kit (version 01.05.00) download link, Release Notes, and Installation Guide.
The Installation Guide recommends you read that entire document before you install. I also recommend you do so. It has useful information that can save you some trouble. For instance, you must uninstall the FDOT Civil 3D 2019 State Kit before installing MR5.
Release Notes are also a necessary read to learn about recent changes to the kit.
As a best practice find and install the updates to AutoCAD 2019, AutoCAD Map 3D 2019, and AutoCAD Civil 3D 2019 before installing FDOT2019 Civil 3D State Kit MR5. Updates can and often do get installed after the FDOT Civil 3D 2019 State Kit is installed without any problems.
Please review my guide to Autodesk Software Updates (published in a mind map format). This guide provides the necessary information required to navigate the overly complex process of finding and installing Autodesk software updates.
If you don’t have a restriction I recommend using Civil 3D 2020 and FDOT2020 Civil 3D State Kit.