FB4 returns an empty string when he can't translate Unicode symbol into ICU-codepage.
FB3 in this case returns an error.
Unicode symbol with code 0x115F (input string 'ᅟ')
Connection charset is NONE.
-- FB3 and FB4 are OK.
select cast(_utf8 'ᅟ' as varchar(1) character set utf8) from rdb$database
-- FB3 returns an error, FB4 OK (an error is expected)
select cast(_utf8 'ᅟ' as varchar(1) character set tis620) from rdb$database
-- FB3 and FB4 return an error (it is OK)
select cast(_utf8 'ᅟ' as varchar(1) character set win1251) from rdb$database
The problem in new implementation of callback function UCNV_FROM_U_CALLBACK_STOP in ICU v63.1
https://github.com/unicode-org/icu/blob/5df4d7dfd8d77dd16aa3a0b398d50a22f4c85daa/icu4c/source/common/ucnv_err.cpp#L68-L113
In ICU v52 (FB3) this function does not contain any code
https://github.com/unicode-org/icu/blob/574e7d9d55760680ea14dbfc4908429a58c5d544/icu4c/source/common/ucnv_err.c#L53-L66
FB4 returns an empty string when he can't translate Unicode symbol into ICU-codepage.
FB3 in this case returns an error.
Unicode symbol with code 0x115F (input string 'ᅟ')
Connection charset is NONE.
The problem in new implementation of callback function UCNV_FROM_U_CALLBACK_STOP in ICU v63.1
https://github.com/unicode-org/icu/blob/5df4d7dfd8d77dd16aa3a0b398d50a22f4c85daa/icu4c/source/common/ucnv_err.cpp#L68-L113
In ICU v52 (FB3) this function does not contain any code
https://github.com/unicode-org/icu/blob/574e7d9d55760680ea14dbfc4908429a58c5d544/icu4c/source/common/ucnv_err.c#L53-L66