Even without the "F Hot" moniker, IDM 6.41 build 20 brought notable improvements over earlier 6.4x releases. According to the official changelog (at the time):
Every cracked build is a gamble. The risk of keyloggers, backdoors, or botnet inclusion far outweighs the benefit of saving $25. internet download manager idm 641 build 20 f hot
Internet Download Manager (IDM) is a popular download manager that accelerates and manages downloads from the internet. It supports various protocols, including HTTP, HTTPS, and FTP. Even without the "F Hot" moniker, IDM 6
One of IDM’s "hottest" features is its ability to panel over web players. Build 20 has been optimized to recognize and download 4K and 8K video streams from popular hosting sites more reliably. Internet Download Manager (IDM) is a popular download
The "hot" or "f" suffix in your query often refers to unofficial "hotfixes" or "cracks" found on third-party sites, which can be extremely dangerous and contain viruses or malware
Beyond the specific Build 20 improvements, this version carries forward major enhancements from the 6.4x series: Enhanced Video Recognition