i18n pot file

[anabell]

> The best CHARSET to use is UTF-8 but of course you have to enter UTF-8
data into the po file. You can write all languages in UTF-8.

But I received this error when I tried filling 'utf-8' :
UnicodeDecodeError: 'utf8' codec can't decode bytes in position 0-1: invalid

> The ENCODING should be 8bit in all cases

Is this the case with Chinese characters too?  I thought its base64?