diff --git a/README.rst b/README.rst
index 89e93e4..be4a76e 100644
--- a/README.rst
+++ b/README.rst
@@ -5,10 +5,10 @@ Bubbly is a package for plotting interactive and animated *bubble charts* using
 
 Dependencies
 ------------
-* Python 3.4+
-* numpy
-* pandas 
-* plotly
+* Python == 3.10.9
+* numpy == 1.25.0
+* pandas == 2.0.3
+* plotly == 5.18.0
 
 Installation
 -------------
diff --git a/bubbly/bubbly.py b/bubbly/bubbly.py
index 8ce96fe..4a7376c 100644
--- a/bubbly/bubbly.py
+++ b/bubbly/bubbly.py
@@ -181,12 +181,14 @@ def make_grid(dataset, column_names, time_column, years=None):
                 # Each column name is unique
                 temp = col_name_template.format(year, col_name)
                 if dataset_by_year[col_name].size != 0:
-                    grid = grid.append({'value': list(dataset_by_year[col_name]), 'key': temp}, ignore_index=True)
+                    # grid = grid.append({'value': list(dataset_by_year[col_name]), 'key': temp}, ignore_index=True)
+                    grid = pd.concat([grid, pd.DataFrame([{'value': list(dataset_by_year[col_name]), 'key': temp}])], ignore_index=True)
     else:
         # Check if this can be simplified
         for col_name in column_names:
             # Each column name is unique
-            grid = grid.append({'value': list(dataset[col_name]), 'key': col_name + '_grid'}, ignore_index=True)
+            # grid = grid.append({'value': list(dataset[col_name]), 'key': col_name + '_grid'}, ignore_index=True)
+            grid = pd.concat([grid, pd.DataFrame([{'value': list(dataset[col_name]), 'key': col_name + '_grid'}])], ignore_index=True)
         
     return grid
 
@@ -210,7 +212,8 @@ def make_grid_with_categories(dataset, column_names, time_column, category_colum
                     # Each column name is unique
                     temp = col_name_template.format(year, col_name, category)
                     if dataset_by_year_and_cat[col_name].size != 0:
-                        grid = grid.append({'value': list(dataset_by_year_and_cat[col_name]), 'key': temp}, ignore_index=True) 
+                        # grid = grid.append({'value': list(dataset_by_year_and_cat[col_name]), 'key': temp}, ignore_index=True) 
+                        grid = pd.concat([grid, pd.DataFrame([{'value': list(dataset_by_year_and_cat[col_name]), 'key': temp}])], ignore_index=True)
     else:
         col_name_template = '{}+{}_grid'
         for category in categories:
@@ -219,7 +222,8 @@ def make_grid_with_categories(dataset, column_names, time_column, category_colum
                 # Each column name is unique
                 temp = col_name_template.format(col_name, category)
                 if dataset_by_cat[col_name].size != 0:
-                        grid = grid.append({'value': list(dataset_by_cat[col_name]), 'key': temp}, ignore_index=True) 
+                        # grid = grid.append({'value': list(dataset_by_cat[col_name]), 'key': temp}, ignore_index=True) 
+                        grid = pd.concat([grid, pd.DataFrame([{'value': list(dataset_by_cat[col_name]), 'key': temp}])], ignore_index=True)
         
     return grid