diff --git a/CI/update_version.py b/CI/update_version.py
index bf63681..5fcf2c1 100644
--- a/CI/update_version.py
+++ b/CI/update_version.py
@@ -3,6 +3,8 @@
 
 import subprocess
 from distutils.version import LooseVersion
+import os
+
 
 def get_version():
     p = subprocess.run(["git describe|sed 's/-/.post/'|cut -d'-' -f1"], shell=True, stdout=subprocess.PIPE)
@@ -10,8 +12,34 @@ def get_version():
     return output
 
 def set_version(version):
+    # modify the files to reflect the new version
+    files = [os.abspath('./src/msspec/__init__.py'),
+             os.abspath('./src/msspec/msspecgui/__init__.py')]
+
+    for f in files:
+        with open(f, "w") as fd:
+            f.write("# Auto-generated file, do not edit\n")
+            f.write(f"__version__ = \"{version}\"\n")
+            f.write(f"__sha__ = \"$Id$\"\n")
+
+    with open(os.abspath("./VERSION"), "w") as fd:
+            f.write(f"MsSpec-{version}")
+
+    # commit them
+    files = [os.abspath('./src/msspec/__init__.py'),
+             os.abspath('./src/msspec/msspecgui/__init__.py'),
+             os.abspath("./VERSION")]
+    for f in files:
+        cmd = ['git', 'add', f]
+        subprocess.run(cmd)
+    msg = 'Update version'
+    cmd = ['git', 'commit', '-m', msg]
+    subprocess.run(cmd)
+
+    # create the tag
     cmd = ['git', 'tag', '-a', version, '-m', f"Python MsSpec ({version})"]
     subprocess.run(cmd)
+    
 
 def ask_new_version(current_version):
     version = LooseVersion(current_version)
diff --git a/VERSION b/VERSION
deleted file mode 100644
index aebc9fe..0000000
--- a/VERSION
+++ /dev/null
@@ -1 +0,0 @@
-MsSpec-1.4post4
diff --git a/src/msspec/__init__.py b/src/msspec/__init__.py
index e53b9b1..5a8aed2 100644
--- a/src/msspec/__init__.py
+++ b/src/msspec/__init__.py
@@ -1 +1 @@
-__version__ = '1.4post4'
+__version__ = '1.5post1'
diff --git a/src/msspec/msspecgui/__init__.py b/src/msspec/msspecgui/__init__.py
index e53b9b1..5a8aed2 100644
--- a/src/msspec/msspecgui/__init__.py
+++ b/src/msspec/msspecgui/__init__.py
@@ -1 +1 @@
-__version__ = '1.4post4'
+__version__ = '1.5post1'