Protocols that are used between Zabbix components are UTF-8 based. However for Windows version of zabbix_get, zabbix_sender no conversion to UTF-8 is done for the command line parameters.

For example, one can query Windows agent from Unix with the following command.

$ ./zabbix_get -s 192.168.3.227 -k "wmi.get[root\cimv2,select Caption from Win32_OperatingSystem where Caption like '%Édition%']"
Microsoft Windows 7 Édition Familiale Premium 

Equivavlent command doesn't work either from PowerShell or cmd.exe.

PS E:\> .\zabbix_get.exe -s 127.0.0.1 -k "wmi.get[root\cimv2,select Caption from Win32_OperatingSystem where Caption like '%Édition%']"
ZBX_NOTSUPPORTED: Cannot obtain WMI information.

We should check how to solve this. One of the possibilities is to change main() to wmain() and then convert arguments from UTF-16 to UTF-8.