diff --git a/README.rst b/README.rst
index ff395b2..d730e28 100644
--- a/README.rst
+++ b/README.rst
@@ -47,6 +47,16 @@ Source links:
 Change history
 ==============
 
+1.5.1 2019-09-09
+----------------
+
+Modified:
+
+* fasta uses natural abundance of H for biomolecule when computing the
+  D2O contrast match rather than the biomolecule with pure H[1].
+* remove half-life units from column header in activation table since
+  each row gives its own units.
+
 1.5.0 2017-05-11
 ----------------
 
diff --git a/periodictable/__init__.py b/periodictable/__init__.py
index 8bf60b9..57f523e 100644
--- a/periodictable/__init__.py
+++ b/periodictable/__init__.py
@@ -28,7 +28,7 @@
 __docformat__ = 'restructuredtext en'
 __all__ = ['elements', 'neutron_sld', 'xray_sld',
            'formula', 'mix_by_weight', 'mix_by_volume'] # and all elements
-__version__ = "1.5.0"
+__version__ = "1.5.1"
 
 from . import core
 from . import mass