diff --git a/lib/filterx/CMakeLists.txt b/lib/filterx/CMakeLists.txt
index 7c3c774eca..fc930ef2b2 100644
--- a/lib/filterx/CMakeLists.txt
+++ b/lib/filterx/CMakeLists.txt
@@ -40,6 +40,7 @@ set(FILTERX_HEADERS
     filterx/func-len.h
     filterx/func-vars.h
     filterx/func-unset-empties.h
+    filterx/func-str-transform.h
     filterx/expr-plus.h
     filterx/expr-null-coalesce.h
     PARENT_SCOPE
@@ -87,6 +88,7 @@ set(FILTERX_SOURCES
     filterx/func-len.c
     filterx/func-vars.c
     filterx/func-unset-empties.c
+    filterx/func-str-transform.c
     filterx/expr-plus.c
     filterx/filterx-private.c
     filterx/expr-null-coalesce.c
diff --git a/lib/filterx/Makefile.am b/lib/filterx/Makefile.am
index e66ed93468..a4f1bb53ab 100644
--- a/lib/filterx/Makefile.am
+++ b/lib/filterx/Makefile.am
@@ -42,6 +42,7 @@ filterxinclude_HEADERS = 			\
 	lib/filterx/func-len.h		\
 	lib/filterx/func-vars.h		\
 	lib/filterx/func-unset-empties.h		\
+	lib/filterx/func-str-transform.h		\
 	lib/filterx/filterx-private.h			\
 	lib/filterx/expr-null-coalesce.h
 
@@ -89,6 +90,7 @@ filterx_sources = 				\
 	lib/filterx/func-len.c		\
 	lib/filterx/func-vars.c		\
 	lib/filterx/func-unset-empties.c		\
+	lib/filterx/func-str-transform.c		\
 	lib/filterx/filterx-private.c	\
 	lib/filterx/expr-null-coalesce.c	\
 	lib/filterx/filterx-grammar.y
diff --git a/lib/filterx/filterx-globals.c b/lib/filterx/filterx-globals.c
index 7ddbcbb06b..a7cfd76745 100644
--- a/lib/filterx/filterx-globals.c
+++ b/lib/filterx/filterx-globals.c
@@ -34,6 +34,7 @@
 #include "filterx/func-len.h"
 #include "filterx/func-vars.h"
 #include "filterx/func-unset-empties.h"
+#include "filterx/func-str-transform.h"
 #include "filterx/filterx-eval.h"
 
 static GHashTable *filterx_builtin_simple_functions = NULL;
@@ -85,7 +86,8 @@ _simple_init(void)
   g_assert(filterx_builtin_simple_function_register("double", filterx_typecast_double));
   g_assert(filterx_builtin_simple_function_register("len", filterx_simple_function_len));
   g_assert(filterx_builtin_simple_function_register("vars", filterx_simple_function_vars));
-
+  g_assert(filterx_builtin_simple_function_register("lower", filterx_simple_function_lower));
+  g_assert(filterx_builtin_simple_function_register("upper", filterx_simple_function_upper));
 }
 
 static void
diff --git a/lib/filterx/func-str-transform.c b/lib/filterx/func-str-transform.c
new file mode 100644
index 0000000000..71b72da075
--- /dev/null
+++ b/lib/filterx/func-str-transform.c
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2024 Axoflow
+ * Copyright (c) 2024 Attila Szakacs
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As an additional exemption you are allowed to compile & link against the
+ * OpenSSL libraries as published by the OpenSSL project. See the file
+ * COPYING for details.
+ *
+ */
+
+#include "filterx/func-str-transform.h"
+#include "filterx/object-string.h"
+#include "filterx/filterx-eval.h"
+
+static const gchar *
+_extract_str_arg(FilterXExpr *s, GPtrArray *args, gssize *len)
+{
+  if (args == NULL || args->len != 1)
+    {
+      filterx_simple_function_argument_error(s, "Requires exactly one argument", FALSE);
+      return NULL;
+    }
+
+  gsize inner_len;
+  FilterXObject *object = g_ptr_array_index(args, 0);
+  const gchar *str = filterx_string_get_value(object, &inner_len);
+  if (!str)
+    {
+      filterx_simple_function_argument_error(s, "Object must be string", FALSE);
+      return NULL;
+    }
+
+  *len = (gssize) MIN(inner_len, G_MAXINT64);
+  return str;
+}
+
+FilterXObject *
+filterx_simple_function_lower(FilterXExpr *s, GPtrArray *args)
+{
+  gssize len;
+  const gchar *str = _extract_str_arg(s, args, &len);
+  if (!str)
+    return NULL;
+
+  gchar *lower = g_utf8_strdown(str, len);
+  FilterXObject *result = filterx_string_new(lower, -1);
+  g_free(lower);
+
+  return result;
+}
+
+FilterXObject *
+filterx_simple_function_upper(FilterXExpr *s, GPtrArray *args)
+{
+  gssize len;
+  const gchar *str = _extract_str_arg(s, args, &len);
+  if (!str)
+    return NULL;
+
+  gchar *upper = g_utf8_strup(str, len);
+  FilterXObject *result = filterx_string_new(upper, -1);
+  g_free(upper);
+
+  return result;
+}
diff --git a/lib/filterx/func-str-transform.h b/lib/filterx/func-str-transform.h
new file mode 100644
index 0000000000..b3d329576c
--- /dev/null
+++ b/lib/filterx/func-str-transform.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2024 Axoflow
+ * Copyright (c) 2024 Attila Szakacs
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As an additional exemption you are allowed to compile & link against the
+ * OpenSSL libraries as published by the OpenSSL project. See the file
+ * COPYING for details.
+ *
+ */
+
+#ifndef FILTERX_FUNC_STR_TRANSFORM_H_INCLUDED
+#define FILTERX_FUNC_STR_TRANSFORM_H_INCLUDED
+
+#include "filterx/expr-function.h"
+
+FilterXObject *filterx_simple_function_lower(FilterXExpr *s, GPtrArray *args);
+FilterXObject *filterx_simple_function_upper(FilterXExpr *s, GPtrArray *args);
+
+#endif
diff --git a/lib/ivykis b/lib/ivykis
index 242a35ab4c..feb0a7f318 160000
--- a/lib/ivykis
+++ b/lib/ivykis
@@ -1 +1 @@
-Subproject commit 242a35ab4c7117ba0692594a16e892495b2d0844
+Subproject commit feb0a7f3185d6300fecb2a8251ba2b2444df029b