diff --git a/driver/connect.c b/driver/connect.c
index f575f710..b75b80fd 100644
--- a/driver/connect.c
+++ b/driver/connect.c
@@ -1311,10 +1311,6 @@ SQLRETURN config_dbc(esodbc_dbc_st *dbc, esodbc_dsn_attrs_st *attrs)
 	dbc->mfield_lenient = wstr2bool(&attrs->mfield_lenient);
 	INFOH(dbc, "multifield lenient: %s.",
 		dbc->mfield_lenient ? "true" : "false");
-	/* "index include frozen" param */
-	dbc->idx_inc_frozen = wstr2bool(&attrs->idx_inc_frozen);
-	INFOH(dbc, "index include frozen: %s.",
-		dbc->idx_inc_frozen ? "true" : "false");
 	/* auto escape pattern value argument */
 	dbc->auto_esc_pva = wstr2bool(&attrs->auto_esc_pva);
 	INFOH(dbc, "auto escape PVA: %s.", dbc->auto_esc_pva ? "true" : "false");
diff --git a/driver/defs.h b/driver/defs.h
index 02f5979b..b056107a 100644
--- a/driver/defs.h
+++ b/driver/defs.h
@@ -178,7 +178,6 @@
 #define ESODBC_DEF_VERSION_CHECKING	ESODBC_DSN_VC_STRICT
 #define ESODBC_DEF_MFIELD_LENIENT	"true"
 #define ESODBC_DEF_ESC_PVA			"true"
-#define ESODBC_DEF_IDX_INC_FROZEN	"false"
 
 /*
  *
diff --git a/driver/dsn.c b/driver/dsn.c
index 70c55e6a..501045ee 100644
--- a/driver/dsn.c
+++ b/driver/dsn.c
@@ -79,7 +79,6 @@ int assign_dsn_attr(esodbc_dsn_attrs_st *attrs,
 		{&MK_WSTR(ESODBC_DSN_VERSION_CHECKING), &attrs->version_checking},
 		{&MK_WSTR(ESODBC_DSN_MFIELD_LENIENT), &attrs->mfield_lenient},
 		{&MK_WSTR(ESODBC_DSN_ESC_PVA), &attrs->auto_esc_pva},
-		{&MK_WSTR(ESODBC_DSN_IDX_INC_FROZEN), &attrs->idx_inc_frozen},
 		{&MK_WSTR(ESODBC_DSN_TRACE_ENABLED), &attrs->trace_enabled},
 		{&MK_WSTR(ESODBC_DSN_TRACE_FILE), &attrs->trace_file},
 		{&MK_WSTR(ESODBC_DSN_TRACE_LEVEL), &attrs->trace_level},
@@ -413,7 +412,6 @@ long TEST_API write_00_list(esodbc_dsn_attrs_st *attrs,
 		{&MK_WSTR(ESODBC_DSN_VERSION_CHECKING), &attrs->version_checking},
 		{&MK_WSTR(ESODBC_DSN_MFIELD_LENIENT), &attrs->mfield_lenient},
 		{&MK_WSTR(ESODBC_DSN_ESC_PVA), &attrs->auto_esc_pva},
-		{&MK_WSTR(ESODBC_DSN_IDX_INC_FROZEN), &attrs->idx_inc_frozen},
 		{&MK_WSTR(ESODBC_DSN_TRACE_ENABLED), &attrs->trace_enabled},
 		{&MK_WSTR(ESODBC_DSN_TRACE_FILE), &attrs->trace_file},
 		{&MK_WSTR(ESODBC_DSN_TRACE_LEVEL), &attrs->trace_level},
@@ -688,11 +686,6 @@ BOOL write_system_dsn(esodbc_dsn_attrs_st *new_attrs,
 			&new_attrs->auto_esc_pva,
 			old_attrs ? &old_attrs->auto_esc_pva : NULL
 		},
-		{
-			&MK_WSTR(ESODBC_DSN_IDX_INC_FROZEN),
-			&new_attrs->idx_inc_frozen,
-			old_attrs ? &old_attrs->idx_inc_frozen : NULL
-		},
 		{
 			&MK_WSTR(ESODBC_DSN_TRACE_ENABLED), &new_attrs->trace_enabled,
 			old_attrs ? &old_attrs->trace_enabled : NULL
@@ -783,7 +776,6 @@ long TEST_API write_connection_string(esodbc_dsn_attrs_st *attrs,
 		{&attrs->version_checking, &MK_WSTR(ESODBC_DSN_VERSION_CHECKING)},
 		{&attrs->mfield_lenient, &MK_WSTR(ESODBC_DSN_MFIELD_LENIENT)},
 		{&attrs->auto_esc_pva, &MK_WSTR(ESODBC_DSN_ESC_PVA)},
-		{&attrs->idx_inc_frozen, &MK_WSTR(ESODBC_DSN_IDX_INC_FROZEN)},
 		{&attrs->trace_enabled, &MK_WSTR(ESODBC_DSN_TRACE_ENABLED)},
 		{&attrs->trace_file, &MK_WSTR(ESODBC_DSN_TRACE_FILE)},
 		{&attrs->trace_level, &MK_WSTR(ESODBC_DSN_TRACE_LEVEL)},
@@ -880,9 +872,6 @@ void assign_dsn_defaults(esodbc_dsn_attrs_st *attrs)
 	res |= assign_dsn_attr(attrs,
 			&MK_WSTR(ESODBC_DSN_ESC_PVA),
 			&MK_WSTR(ESODBC_DEF_ESC_PVA), /*overwrite?*/FALSE);
-	res |= assign_dsn_attr(attrs,
-			&MK_WSTR(ESODBC_DSN_IDX_INC_FROZEN),
-			&MK_WSTR(ESODBC_DEF_IDX_INC_FROZEN), /*overwrite?*/FALSE);
 
 	/* default: no trace file */
 	res |= assign_dsn_attr(attrs,
diff --git a/driver/dsn.h b/driver/dsn.h
index 57e940cd..0f71ec9c 100644
--- a/driver/dsn.h
+++ b/driver/dsn.h
@@ -38,7 +38,6 @@
 #define ESODBC_DSN_VERSION_CHECKING	"VersionChecking"
 #define ESODBC_DSN_MFIELD_LENIENT	"MultiFieldLenient"
 #define ESODBC_DSN_ESC_PVA			"AutoEscapePVA"
-#define ESODBC_DSN_IDX_INC_FROZEN	"IndexIncludeFrozen"
 #define ESODBC_DSN_TRACE_ENABLED	"TraceEnabled"
 #define ESODBC_DSN_TRACE_FILE		"TraceFile"
 #define ESODBC_DSN_TRACE_LEVEL		"TraceLevel"
@@ -80,11 +79,10 @@ typedef struct {
 	wstr_st version_checking;
 	wstr_st mfield_lenient;
 	wstr_st auto_esc_pva;
-	wstr_st idx_inc_frozen;
 	wstr_st trace_enabled;
 	wstr_st trace_file;
 	wstr_st trace_level;
-#define ESODBC_DSN_ATTRS_COUNT	27
+#define ESODBC_DSN_ATTRS_COUNT	26
 	SQLWCHAR buff[ESODBC_DSN_ATTRS_COUNT * ESODBC_DSN_MAX_ATTR_LEN];
 	/* DSN reading/writing functions are passed a SQLSMALLINT lenght param */
 #if SHRT_MAX < ESODBC_DSN_ATTRS_COUNT * ESODBC_DSN_MAX_ATTR_LEN
diff --git a/driver/handles.h b/driver/handles.h
index 22f72068..c0e7528a 100644
--- a/driver/handles.h
+++ b/driver/handles.h
@@ -163,7 +163,6 @@ typedef struct struct_dbc {
 		ESODBC_FLTS_AUTO,
 	} sci_floats; /* floats printing on conversion */
 	BOOL mfield_lenient; /* 'field_multi_value_leniency' request param */
-	BOOL idx_inc_frozen; /* 'field_multi_value_leniency' request param */
 	BOOL auto_esc_pva; /* auto-escape PVA args in catalog functions */
 
 	esodbc_estype_st *es_types; /* array with ES types */
diff --git a/driver/queries.c b/driver/queries.c
index 65249747..2d3b113f 100644
--- a/driver/queries.c
+++ b/driver/queries.c
@@ -2048,17 +2048,6 @@ static SQLRETURN serialize_params(esodbc_stmt_st *stmt, char *dest,
 #	undef JSON_KEY_VALUE
 }
 
-static inline size_t copy_bool_val(char *dest, BOOL val)
-{
-	if (val) {
-		memcpy(dest, "true", sizeof("true") - 1);
-		return sizeof("true") - 1;
-	} else {
-		memcpy(dest, "false", sizeof("false") - 1);
-		return sizeof("false") - 1;
-	}
-}
-
 /*
  * Build a serialized JSON object out of the statement.
  * If resulting string fits into the given buff, the result is copied in it;
@@ -2120,9 +2109,6 @@ SQLRETURN TEST_API serialize_statement(esodbc_stmt_st *stmt, cstr_st *buff)
 		/* "field_multi_value_leniency": true/false */
 		bodylen += sizeof(JSON_KEY_MULTIVAL) - 1;
 		bodylen += /*false*/5;
-		/* "index_include_frozen": true/false */
-		bodylen += sizeof(JSON_KEY_IDX_FROZEN) - 1;
-		bodylen += /*false*/5;
 		/* "time_zone": "-05:45" */
 		bodylen += sizeof(JSON_KEY_TIMEZONE) - 1;
 		bodylen += tz_param.cnt;
@@ -2200,12 +2186,13 @@ SQLRETURN TEST_API serialize_statement(esodbc_stmt_st *stmt, cstr_st *buff)
 		/* "field_multi_value_leniency": true/false */
 		memcpy(body + pos, JSON_KEY_MULTIVAL, sizeof(JSON_KEY_MULTIVAL) - 1);
 		pos += sizeof(JSON_KEY_MULTIVAL) - 1;
-		pos += copy_bool_val(body + pos, dbc->mfield_lenient);
-		/* "index_include_frozen": true/false */
-		memcpy(body + pos, JSON_KEY_IDX_FROZEN,
-				sizeof(JSON_KEY_IDX_FROZEN) - 1);
-		pos += sizeof(JSON_KEY_IDX_FROZEN) - 1;
-		pos += copy_bool_val(body + pos, dbc->idx_inc_frozen);
+		if (dbc->mfield_lenient) {
+			memcpy(body + pos, "true", sizeof("true") - 1);
+			pos += sizeof("true") - 1;
+		} else {
+			memcpy(body + pos, "false", sizeof("false") - 1);
+			pos += sizeof("false") - 1;
+		}
 		/* "time_zone": "-05:45" */
 		memcpy(body + pos, JSON_KEY_TIMEZONE, sizeof(JSON_KEY_TIMEZONE) - 1);
 		pos += sizeof(JSON_KEY_TIMEZONE) - 1;
@@ -2213,9 +2200,8 @@ SQLRETURN TEST_API serialize_statement(esodbc_stmt_st *stmt, cstr_st *buff)
 			memcpy(body + pos, tz_param.str, tz_param.cnt);
 			pos += tz_param.cnt;
 		} else {
-			memcpy(body + pos, JSON_VAL_TIMEZONE_Z,
-				sizeof(JSON_VAL_TIMEZONE_Z) - 1);
-			pos += sizeof(JSON_VAL_TIMEZONE_Z) - 1;
+			memcpy(body + pos, "\"Z\"", sizeof("\"Z\"") - 1);
+			pos += sizeof("\"Z\"") - 1;
 		}
 
 		/* reset the page counter when the params change */
diff --git a/driver/queries.h b/driver/queries.h
index 322feb79..f06618c1 100644
--- a/driver/queries.h
+++ b/driver/queries.h
@@ -140,10 +140,7 @@ SQLRETURN EsSQLRowCount(_In_ SQLHSTMT StatementHandle, _Out_ SQLLEN *RowCount);
 #	define JSON_KEY_CLT_ID		", \"client_id\": \"odbc32\"" /* n-th k. */
 #endif /* _WIN64 */
 #define JSON_KEY_MULTIVAL		", \"field_multi_value_leniency\": " /* n-th */
-#define JSON_KEY_IDX_FROZEN		", \"index_include_frozen\": " /* n-th */
 #define JSON_KEY_TIMEZONE		", \"time_zone\": " /* n-th key */
 
-#define JSON_VAL_TIMEZONE_Z		"\"Z\""
-
 
 #endif /* __QUERIES_H__ */
diff --git a/test/connected_dbc.cc b/test/connected_dbc.cc
index c10f9001..69aecd0c 100644
--- a/test/connected_dbc.cc
+++ b/test/connected_dbc.cc
@@ -169,7 +169,6 @@ void ConnectedDBC::assertRequest(const char *params, const char *tz)
 		JSON_KEY_QUERY "\"%s\""
 		JSON_KEY_PARAMS "%s"
 		JSON_KEY_MULTIVAL ESODBC_DEF_MFIELD_LENIENT
-		JSON_KEY_IDX_FROZEN ESODBC_DEF_IDX_INC_FROZEN
 		JSON_KEY_TIMEZONE "%s%s%s"
 		JSON_KEY_VAL_MODE
 		JSON_KEY_CLT_ID
@@ -186,7 +185,7 @@ void ConnectedDBC::assertRequest(const char *params, const char *tz)
 				"\"", tz, "\"");
 	} else {
 		n = snprintf(expect, sizeof(expect), answ_templ, test_name, params,
-				"", JSON_VAL_TIMEZONE_Z, "");
+				"", "\"Z\"", "");
 	}
 	ASSERT_LT(actual.cnt, sizeof(expect));
 	ASSERT_EQ(n, actual.cnt);