diff --git a/felt/core/fsl_converter.py b/felt/core/fsl_converter.py
index d1fb190..b1a0967 100644
--- a/felt/core/fsl_converter.py
+++ b/felt/core/fsl_converter.py
@@ -1610,7 +1610,7 @@ def paletted_renderer_to_fsl(
         colors = []
         labels = {}
         for _class in renderer.classes():
-            categories.append(_class.value)
+            categories.append(str(_class.value))
             colors.append(_class.color.name())
             labels[str(_class.value)] = _class.label
         return {
diff --git a/felt/core/layer_exporter.py b/felt/core/layer_exporter.py
index 62992e4..7b34b86 100644
--- a/felt/core/layer_exporter.py
+++ b/felt/core/layer_exporter.py
@@ -243,7 +243,7 @@ def representative_layer_style(
             )
 
         if fsl:
-            fsl['version'] = '2.1'
+            fsl['version'] = '2.1.1'
 
         return LayerStyle(
             fsl=fsl
diff --git a/felt/test/test_fsl_conversion.py b/felt/test/test_fsl_conversion.py
index b63e29a..9d19441 100644
--- a/felt/test/test_fsl_conversion.py
+++ b/felt/test/test_fsl_conversion.py
@@ -2010,7 +2010,7 @@ def test_convert_paletted_raster(self):
 
         self.assertEqual(FslConverter.raster_renderer_to_fsl(
             renderer, context),
-            {'config': {'band': 1, 'categories': [120.0, 125.0, 130.0]},
+            {'config': {'band': 1, 'categories': ['120.0', '125.0', '130.0']},
              'legend': {'displayName': {'120.0': 'lowest',
                                         '125.0': 'mid',
                                         '130.0': 'highest'}},
@@ -2026,7 +2026,7 @@ def test_convert_paletted_raster(self):
 
         self.assertEqual(FslConverter.raster_renderer_to_fsl(
             renderer, context),
-            {'config': {'band': 2, 'categories': [120.0, 125.0, 130.0]},
+            {'config': {'band': 2, 'categories': ['120.0', '125.0', '130.0']},
              'legend': {'displayName': {'120.0': 'lowest',
                                         '125.0': 'mid',
                                         '130.0': 'highest'}},