You can access the latest version of HotA by following one of a number of interchangeable links. If you encounter problems with downloading, try another one:
https://www.vault.acidcave.net/download.php?id=614
https://heroes.chubr.cf/HotA_1.6.1_setup.exe
https://drive.google.com/open?id=1eAOPZbg62ucgY1_853yQLjS4-wYSwqmr
https://mirrorace.com/m/3CO6q
https://www.mediafire.com/file/vrq4jvjxwt313dv/HotA_1.6.1_setup.exe/file
http://heroes3towns.com/HotA/HotA_1.6.1_setup.exe
http://h3hota.com/storage/HotA_1.6.1_setup.exe.torrent
If there are issues when performing an automated update of the HD-Mod, you can download the up-to-date installer package from the developer’s website and install it over the old version in the same folder.