diff --git a/pyopia/__init__.py b/pyopia/__init__.py
index 5752f76..c292939 100644
--- a/pyopia/__init__.py
+++ b/pyopia/__init__.py
@@ -1 +1 @@
-__version__ = '2.5.6'
+__version__ = '2.5.7'
diff --git a/pyopia/io.py b/pyopia/io.py
index dff5db1..7e75a5a 100644
--- a/pyopia/io.py
+++ b/pyopia/io.py
@@ -196,7 +196,7 @@ def combine_stats_netcdf_files(path_to_data, prefix='*'):
         Folder name containing nc files with pattern '*Image-D*-STATS.nc'
 
     prefix : str
-        Prefix to multi-file dataset (for replacing the wildcard in '*Image-D*-STATS.nc').
+        Prefix to multi-file dataset (for replacing <prefix> in the file name pattern '<prefix>Image-D*-STATS.nc').
         Defaults to '*'
 
     Returns