diff --git a/tests/bugs/core_5020_test.py b/tests/bugs/core_5020_test.py
index 154befeb..8f1a84fd 100644
--- a/tests/bugs/core_5020_test.py
+++ b/tests/bugs/core_5020_test.py
@@ -5,16 +5,25 @@ ID:          issue-5308
 ISSUE:       5308
 TITLE:       Regression: ORDER BY clause on compound index may disable usage of other indices
 DESCRIPTION:
+    Plan in 3.0.0.32179 (before fix): PLAN (ZF ORDER IXA_FK__ID__KONT_ID)
+    Fixed in 3.0 since: http://sourceforge.net/p/firebird/code/62570
+    Checked on 2.5.5.26952 - plans are the same now.
 JIRA:        CORE-5020
 FBTEST:      bugs.core_5020
+NOTES:
+    [17.11.2024] pzotov
+    Re-implemented after https://github.com/FirebirdSQL/firebird/commit/26e64e9c08f635d55ac7a111469498b3f0c7fe81
+    ( Cost-based decision between ORDER and SORT plans (#8316) ).
+    Execution plan was replaced with explained. Plans are splitted for versions up to 5.x and 6.x+.
+    Discussed with dimitr, letters 16.11.2024.
+
+    Checked on 6.0.0.532; 5.0.2.1567; 4.0.6.3168; 3.0.13.33794.
 """
 
 import pytest
 from firebird.qa import *
 
-db = db_factory()
-
-test_script = """
+init_sql = """
     recreate table zf(
         id integer not null primary key,
         kont_id integer not null
@@ -76,28 +85,64 @@ test_script = """
 
     create index ixa_fk__id__kont_id on zf(id, kont_id);
     commit;
-
-    set planonly;
-    select zf.*
-    from zf
-    where zf.kont_id=5
-    order by zf.id, kont_id;
-
-    -- Plan in 3.0.0.32179 (before fix): PLAN (ZF ORDER IXA_FK__ID__KONT_ID)
-    -- Fixed in 3.0 since: http://sourceforge.net/p/firebird/code/62570
-    -- Checked on 2.5.5.26952 - plans are the same now.
-
 """
 
-act = isql_act('db', test_script)
+db = db_factory(init = init_sql)
+act = python_act('db', substitutions = [(r'record length: \d+, key length: \d+', 'record length: NN, key length: MM')])
 
-expected_stdout = """
-    PLAN (ZF ORDER IXA_FK__ID__KONT_ID INDEX (FK_ZF__K))
-"""
+#-----------------------------------------------------------
+
+def replace_leading(source, char="."):
+    stripped = source.lstrip()
+    return char * (len(source) - len(stripped)) + stripped
+
+#-----------------------------------------------------------
 
 @pytest.mark.version('>=3')
-def test_1(act: Action):
-    act.expected_stdout = expected_stdout
-    act.execute()
-    assert act.clean_stdout == act.clean_expected_stdout
+def test_1(act: Action, capsys):
+    test_sql = """
+        select zf.*
+        from zf
+        where zf.kont_id=5
+        order by zf.id, kont_id
+    """
 
+    with act.db.connect() as con:
+        cur = con.cursor()
+        ps = None
+        try:
+            ps = cur.prepare(test_sql)
+
+            # Print explained plan with padding eash line by dots in order to see indentations:
+            print( '\n'.join([replace_leading(s) for s in ps.detailed_plan.split('\n')]) )
+            print('')
+        except DatabaseError as e:
+            print(e.__str__())
+            print(e.gds_codes)
+        finally:
+            if ps:
+                ps.free()
+
+
+    expected_stdout_5x = """
+        Select Expression
+        ....-> Filter
+        ........-> Table "ZF" Access By ID
+        ............-> Index "IXA_FK__ID__KONT_ID" Full Scan
+        ................-> Bitmap
+        ....................-> Index "FK_ZF__K" Range Scan (full match)
+    """
+
+    expected_stdout_6x = """
+        Select Expression
+        ....-> Sort (record length: 36, key length: 16)
+        ........-> Filter
+        ............-> Table "ZF" Access By ID
+        ................-> Bitmap
+        ....................-> Index "FK_ZF__K" Range Scan (full match)
+    """
+
+    act.expected_stdout = expected_stdout_5x if act.is_version('<6') else expected_stdout_6x
+
+    act.stdout = capsys.readouterr().out
+    assert act.clean_stdout == act.clean_expected_stdout