Au KDDI (44007)
- Alphanumeric Sender IDs are supported, numeric Sender IDs will be changed to randomised numeric senderIDs.
NTT Docomo (44010) & Softbank Mobile (44020)
- Alphanumeric Sender IDs are supported, numeric Sender IDs will be changed to NXSMS.
Gambling related content are not supported towards Japan all networks.
Messages classified as illegal by the local networks are either discarded completely or part of the illegal text will be removed
Unicode messages are supported when the content is Japanese characters.
For other languages, some handsets may not be able to display them correctly, or messages may not be delivered (e.g. Chinese).
Concatenated messages are currently not supported, meaning there is a max of 140 bytes (160 GSM7 characters/ 70 unicode characters) for all Japan networks. SMS that are longer than this would be split into multiple parts of SMS and delivered individually.
Other features/restrictions of note:
Delivery Receipts should not be relied upon.