Domino may receive messages which are encoded by RFC2047 for the non-ASCII filename (Japanese) from a system other than Domino.
However, the current release of Domino cannot detect the encoded message by RFC2047..
So, attachment file name cannot be converted properly when it is decoded on Domino server or Notes client.
This phenomenon was reported to the development team with SPR # TKAACKL3NF.
Gmail and Yahoo Mail both handle this the same way as Domino.
They detect the 2031 encoding
However, RFC2047 is also the correct encoding method, and we can expect more mail systems to adopt it in the future.
Therefore, we would like Notes/Domino to support RFC2047 encoding as well.