This is going to be a very short guide.  It will help you keep up to date with the current map as well as delete old maps in case you accidentally host an older version on accident “like I do”.

First off, you can download the most current version on the website under “download map” or on discord in the “map-version” text channel under “Welcome”.

After you download the map, you should get a W3X file in your “download folder”.  After you have this go to your (Users > Documents > Warcraft III > Maps > Download).  Drag the W3X file here.  As stated earlier, if you have a problem with hosting outdated versions of maps, you can also delete them now.  This works for any custom game, not just Pyro TD.