diff --git a/src/common/intlobj_new.h b/src/common/intlobj_new.h
index 395d725e26..dfaa8d9d16 100644
--- a/src/common/intlobj_new.h
+++ b/src/common/intlobj_new.h
@@ -275,8 +275,9 @@ typedef void (*pfn_INTL_cs_destroy) (
 #define CHARSET_VERSION_1	1
 
 /* charset flag values */
-#define CHARSET_LEGACY_SEMANTICS 1 /* MBCS strings may overflow declared lengths
-                                      in characters (but not in bytes) */
+
+/* MBCS strings may overflow declared lengths in characters (but not in bytes) */
+/* Removed from FB 4 - #define CHARSET_LEGACY_SEMANTICS 1 */
 
 #define CHARSET_ASCII_BASED 2 /* Value of ASCII characters is equal to the
                                  ASCII character set */
diff --git a/src/intl/cs_big5.cpp b/src/intl/cs_big5.cpp
index 4d5f2d3a00..c115aa7053 100644
--- a/src/intl/cs_big5.cpp
+++ b/src/intl/cs_big5.cpp
@@ -33,7 +33,7 @@ CHARSET_ENTRY(CS_big_5)
 
 	csptr->charset_version = CHARSET_VERSION_1;
 	csptr->charset_name = POSIX;
-	csptr->charset_flags |= CHARSET_LEGACY_SEMANTICS | CHARSET_ASCII_BASED;
+	csptr->charset_flags |= CHARSET_ASCII_BASED;
 	csptr->charset_min_bytes_per_char = 1;
 	csptr->charset_max_bytes_per_char = 2;
 	csptr->charset_space_length = 1;
diff --git a/src/intl/cs_gb2312.cpp b/src/intl/cs_gb2312.cpp
index eb150dcfd8..09aafad3df 100644
--- a/src/intl/cs_gb2312.cpp
+++ b/src/intl/cs_gb2312.cpp
@@ -33,7 +33,7 @@ CHARSET_ENTRY(CS_gb_2312)
 
 	csptr->charset_version = CHARSET_VERSION_1;
 	csptr->charset_name = POSIX;
-	csptr->charset_flags |= CHARSET_LEGACY_SEMANTICS | CHARSET_ASCII_BASED;
+	csptr->charset_flags |= CHARSET_ASCII_BASED;
 	csptr->charset_min_bytes_per_char = 1;
 	csptr->charset_max_bytes_per_char = 2;
 	csptr->charset_space_length = 1;
diff --git a/src/intl/cs_jis.cpp b/src/intl/cs_jis.cpp
index e45358a201..b1f6846c00 100644
--- a/src/intl/cs_jis.cpp
+++ b/src/intl/cs_jis.cpp
@@ -56,7 +56,6 @@ CHARSET_ENTRY(CS_sjis)
 {
 	CS_jis_0208_1990(csptr, NULL); //, cs_name); Second param is unused
 	csptr->charset_name = "SJIS";
-	csptr->charset_flags |= CHARSET_LEGACY_SEMANTICS;
 	csptr->charset_min_bytes_per_char = 1;
 	csptr->charset_space_length = 1;
 	csptr->charset_space_character = (const BYTE*) " ";	// 0x20
@@ -71,7 +70,6 @@ CHARSET_ENTRY(CS_euc_j)
 {
 	CS_jis_0208_1990(csptr, NULL); //cs_name); Second param is unused
 	csptr->charset_name = "EUC-J";
-	csptr->charset_flags |= CHARSET_LEGACY_SEMANTICS;
 	csptr->charset_min_bytes_per_char = 1;
 	csptr->charset_space_length = 1;
 	csptr->charset_space_character = (const BYTE*) " ";	// 0x20
diff --git a/src/intl/cs_ksc.cpp b/src/intl/cs_ksc.cpp
index ad8ed7fd85..9bbfe823da 100644
--- a/src/intl/cs_ksc.cpp
+++ b/src/intl/cs_ksc.cpp
@@ -34,7 +34,7 @@ CHARSET_ENTRY(CS_ksc_5601)
 
 	csptr->charset_version = CHARSET_VERSION_1;
 	csptr->charset_name = "KSC_5601";
-	csptr->charset_flags |= CHARSET_LEGACY_SEMANTICS | CHARSET_ASCII_BASED;
+	csptr->charset_flags |= CHARSET_ASCII_BASED;
 	csptr->charset_min_bytes_per_char = 1;
 	csptr->charset_max_bytes_per_char = 2;
 	csptr->charset_space_length = 1;
diff --git a/src/intl/cs_unicode_fss.cpp b/src/intl/cs_unicode_fss.cpp
index 7102d4c3ca..49dbd674b9 100644
--- a/src/intl/cs_unicode_fss.cpp
+++ b/src/intl/cs_unicode_fss.cpp
@@ -32,7 +32,7 @@ CHARSET_ENTRY(CS_unicode_fss)
 {
 	csptr->charset_version = CHARSET_VERSION_1;
 	csptr->charset_name = "UNICODE_FSS";
-	csptr->charset_flags |= CHARSET_LEGACY_SEMANTICS | CHARSET_ASCII_BASED;
+	csptr->charset_flags |= CHARSET_ASCII_BASED;
 	csptr->charset_min_bytes_per_char = 1;
 	csptr->charset_max_bytes_per_char = 3;
 	csptr->charset_space_length = 1;
diff --git a/src/jrd/cvt.cpp b/src/jrd/cvt.cpp
index 9648618160..c0ffb2e122 100644
--- a/src/jrd/cvt.cpp
+++ b/src/jrd/cvt.cpp
@@ -419,9 +419,7 @@ void EngineCallbacks::validateData(CharSet* toCharSet, SLONG length, const UCHAR
 void EngineCallbacks::validateLength(CharSet* toCharSet, SLONG toLength, const UCHAR* start,
 	const USHORT to_size)
 {
-	if (toCharSet &&
-		toCharSet->isMultiByte() &&
-		!(toCharSet->getFlags() & CHARSET_LEGACY_SEMANTICS))
+	if (toCharSet && toCharSet->isMultiByte())
 	{
 		Jrd::thread_db* tdbb = NULL;
 		SET_TDBB(tdbb);
diff --git a/src/jrd/intl.cpp b/src/jrd/intl.cpp
index 6b5fcf9f0a..b5e181a99f 100644
--- a/src/jrd/intl.cpp
+++ b/src/jrd/intl.cpp
@@ -547,32 +547,9 @@ void INTL_adjust_text_descriptor(thread_db* tdbb, dsc* desc)
 		{
 			Firebird::HalfStaticArray<UCHAR, BUFFER_SMALL> buffer;
 
-			if (charSet->getFlags() & CHARSET_LEGACY_SEMANTICS)
-			{
-				desc->dsc_length = charSet->substring(TEXT_LEN(desc), desc->dsc_address, TEXT_LEN(desc),
-										buffer.getBuffer(TEXT_LEN(desc) * charSet->maxBytesPerChar()), 0,
-										TEXT_LEN(desc));
-
-				const ULONG maxLength = TEXT_LEN(desc) / charSet->maxBytesPerChar();
-				ULONG charLength = charSet->length(desc->dsc_length, desc->dsc_address, true);
-
-				while (charLength > maxLength)
-				{
-					if (desc->dsc_address[desc->dsc_length - 1] == *charSet->getSpace())
-					{
-						--desc->dsc_length;
-						--charLength;
-					}
-					else
-						break;
-				}
-			}
-			else
-			{
-				desc->dsc_length = charSet->substring(TEXT_LEN(desc), desc->dsc_address,
-										TEXT_LEN(desc), buffer.getBuffer(TEXT_LEN(desc)), 0,
-										TEXT_LEN(desc) / charSet->maxBytesPerChar());
-			}
+			desc->dsc_length = charSet->substring(TEXT_LEN(desc), desc->dsc_address,
+				TEXT_LEN(desc), buffer.getBuffer(TEXT_LEN(desc)), 0,
+				TEXT_LEN(desc) / charSet->maxBytesPerChar());
 		}
 	}
 }
@@ -951,9 +928,7 @@ int INTL_convert_string(dsc* to, const dsc* from, ErrorFunction err)
 	const ULONG src_len = toCharSet->length(toLength, start, false);
 	const ULONG dest_len  = (ULONG) to_size / toCharSet->maxBytesPerChar();
 
-	if (toCharSet->isMultiByte() &&
-		!(toCharSet->getFlags() & CHARSET_LEGACY_SEMANTICS) &&
-		src_len > dest_len)
+	if (toCharSet->isMultiByte() && src_len > dest_len)
 	{
 		err(Arg::Gds(isc_arith_except) << Arg::Gds(isc_string_truncation) <<
 			Arg::Gds(isc_trunc_limits) << Arg::Num(dest_len) << Arg::Num(src_len));
diff --git a/src/jrd/intl_builtin.cpp b/src/jrd/intl_builtin.cpp
index 30c958a588..36664c5ac6 100644
--- a/src/jrd/intl_builtin.cpp
+++ b/src/jrd/intl_builtin.cpp
@@ -1459,7 +1459,6 @@ static INTL_BOOL cs_unicode_fss_init(charset* csptr,
 
 	IntlUtil::initNarrowCharset(csptr, "UNICODE_FSS");
 	csptr->charset_max_bytes_per_char = 3;
-	csptr->charset_flags |= CHARSET_LEGACY_SEMANTICS;
 
 	IntlUtil::initConvert(&csptr->charset_to_unicode, internal_fss_to_unicode);
 	IntlUtil::initConvert(&csptr->charset_from_unicode, internal_unicode_to_fss);