Rehlds is a result of reverse engineering of original HLDS (build 6152/6153) using DWARF debug info embedded into linux version of HLDS, engine_i486.so
Along with reverse engineering, a lot of defects and (potential) bugs were found and fixed
Rehlds is fully compatible with latest official HLDS downloaded by steamcmd. All you have to do is to download rehlds binaries and replace original swds.dll/engine_i486.so. For windows you can also copy a swds.pdb file with a debug information.
<br/><b>Warning!</b> Rehlds is not compatible with an old 5xxx or below platforms downloaded by hldsupdatetool.
Archive's bin directory contains 2 subdirectories, 'bugfixed' and 'pure'
<ul>
<li>'pure' version is designed to work exactly as official hlds engine</li>
<li>'bugfixed' version contains some fixes and improvements</li>
</ul>
<b>Warning!</b> Rehlds is not binary compatible with original hlds since it's compiled with compilers other than ones used for original hlds. This means that plugins that do binary code analysis (Orpheu for example) probably will not work with rehlds.
<li>sv_rehlds_userinfo_transmitted_fields // Userinfo fields only with these keys will be transmitted to clients via network. If not set then all fields will be transmitted (except prefixed with underscore). Each key must be prefixed by backslash, for example "\name\model\*sid\*hltv\bottomcolor\topcolor". Default: ""