DeserializationError::NotSupported when the input document contains a feature that is not supported by the library.
ArduinoJson can decode Unicode escape sequence, but this feature is disabled by default because it makes the code bigger. To enable it, you must define ARDUINOJSON_DECODE_UNICODE to
1, like that:
#define ARDUINOJSON_DECODE_UNICODE 1 #include <ArduinoJson.h>
Please note that the support for Unicode escape sequence is not fully compliant with the specification. ArduinoJson produces proper UTF-8 only for code points below 0x10000. Above this limit, it produces a degenerated variant of UTF-8 know as CESU-8. Simply put, ArduinoJson treats surrogate pairs (characters that require two escape sequences) as two independent characters.
Here is the list of supported features: