Experts only

Rollback
The number of bytes that will be requested from the remote user that overlap the existing incomplete file on disk.  The overlapping bytes are compared, and if they do not match, the source is judged to be incompatible, and is removed with a "Rollback inconsistency, existing file does not match the one being downloaded" error. This value normally has no effect when Advanced Resume is enabled. (default: 4096)
Max Hash Speed
Measured in mebibytes per second. (no default)
Write Buffer Size
Measured in kibibytes. (default: 16)
Max Tab Rows
The maximum number of rows of tabs that DC++ will make. Any tabs that do not fit will be accessible through the chevron at the right of the tab control. (default: 2)
PM history
The number of lines that will be read from the private message log and displayed when a new PM is received.  (default: 0)
Search history
Number of old searchlines that will be shown on searchpage. (default: 10)
Mini slot size
Define the size of the mini slot. Can not be defined as lower than 64 KiB. (default: 64 KiB)
Bind address
This is an advanced setting that allows you to set a bind address for DC++ to use. Normally this is 0.0.0.0 and most users do not want to change this. If you however have two network interfaces connected to the internet, it can be useful to change this. Set one of your local IP addresses here, DC++ will then only use that particular network interface for all connections. If binding fails, it will do so silently and INADDR_ANY will be used instead. If you experience connection problems make sure that this is set to default. (default: 0.0.0.0)
This feature requires a restart to be fully effective.