This is a major update of the plugin interface. Now plugins can actively influence the debugging process. They may set temporary breakpoints (Plugintempbreakpoint()) and receive notifications if breakpoint is hit (ODBG2_Plugintempbreakpoint()). If they receive exception notification, ODBG2_Pluginexception() may request to pause application or step over this exception. ODBG2_Pluginnotify() is extended and can force different mode of execution than requested by user.
If necessary, plugin may create one or several options pages in a new Plugins options dialog, which is very similar to the Options. Pluginshowoptions() directly opens plugin-related options page.
There is a new sample plugin, traceapi.dll, that demonstrates new features. It uses one-time memory breakpoints to detect all calls from the user code to the Windows API and protocols the arguments and values returned by APIs.
Plugin documentation is still far away from finished but is strongly updated.
OllyDbg itself got several bugfixes and minor improvements.