An 1.1 compliant frontend should:
1) check for sane version >= 1.1 (a macro will be provided) 2) call sane_control_option int supported_version = SOMEMACRO(1,1); sane_control_option(handle, 0, SANE_ACTION_XXXX, &supported_version, NULL); 3) the backend can then expose sane 1.1 features. I can check every backend driver to see if they can handle a previously unknown SANE_ACTION_XXX and eventually fix them. A frontend that declares itself 1.1 capable should be able to handle unknown frame formats and, generally, be able to correctly use the default: label of any switch statement to handle an unknown condition. Especially when dealing with enums, it is a good practice to not assume that an enum will always have a fixed amount of entries. -- Best regards, Alessandro Zummo, Tower Technologies - Torino, Italy http://www.towertech.it