diff --git a/extract.js b/extract.js
index 3c76941..0aa6d90 100644
--- a/extract.js
+++ b/extract.js
@@ -78,6 +78,12 @@ const extractConfig = dom => {
   const head = xpath.select('/ttFont/head', dom, true);
   const hhea = xpath.select('/ttFont/hhea', dom, true);
 
+  // remove elements that change after each save
+  // but we don't care about
+  head.removeChild(xpath.select('checkSumAdjustment', head, true));
+  head.removeChild(xpath.select('created', head, true));
+  head.removeChild(xpath.select('modified', head, true));
+
   const bbox = extractFromPath('/ttFont/CFF/CFFFont/FontBBox', dom);
   const widthX = extractFromPath(
     '/ttFont/CFF/CFFFont/Private/nominalWidthX',
diff --git a/ligature/OperatorMonoLig-Light/config.xml b/ligature/OperatorMonoLig-Light/config.xml
index 6a44b16..fd0a4e9 100644
--- a/ligature/OperatorMonoLig-Light/config.xml
+++ b/ligature/OperatorMonoLig-Light/config.xml
@@ -11,8 +11,6 @@
         <fontRevision value="1.002"/>
         
     
-        <checkSumAdjustment value="0xb9a318ef"/>
-        
     
         <magicNumber value="0x5f0f3cf5"/>
         
@@ -23,11 +21,7 @@
         <unitsPerEm value="1000"/>
         
     
-        <created value="Fri Apr 27 15:41:11 2018"/>
-        
     
-        <modified value="Fri Apr 27 15:41:11 2018"/>
-        
     
         <xMin value="-1018"/>
         
diff --git a/ligature/OperatorMonoLig-LightItalic/config.xml b/ligature/OperatorMonoLig-LightItalic/config.xml
index 869b5bc..3ff8b7b 100644
--- a/ligature/OperatorMonoLig-LightItalic/config.xml
+++ b/ligature/OperatorMonoLig-LightItalic/config.xml
@@ -11,8 +11,6 @@
         <fontRevision value="1.002"/>
         
     
-        <checkSumAdjustment value="0x7d28ec7a"/>
-        
     
         <magicNumber value="0x5f0f3cf5"/>
         
@@ -23,11 +21,7 @@
         <unitsPerEm value="1000"/>
         
     
-        <created value="Mon Apr 30 12:56:41 2018"/>
-        
     
-        <modified value="Mon Apr 30 12:56:41 2018"/>
-        
     
         <xMin value="-487"/>
         
diff --git a/ligature/OperatorMonoSSmLig-Book/config.xml b/ligature/OperatorMonoSSmLig-Book/config.xml
index e57754c..1b1ba88 100644
--- a/ligature/OperatorMonoSSmLig-Book/config.xml
+++ b/ligature/OperatorMonoSSmLig-Book/config.xml
@@ -11,8 +11,6 @@
         <fontRevision value="1.002"/>
         
     
-        <checkSumAdjustment value="0xfa6956ba"/>
-        
     
         <magicNumber value="0x5f0f3cf5"/>
         
@@ -23,11 +21,7 @@
         <unitsPerEm value="1000"/>
         
     
-        <created value="Wed Apr 17 14:51:05 2019"/>
-        
     
-        <modified value="Wed Apr 17 14:51:05 2019"/>
-        
     
         <xMin value="-1773"/>
         
diff --git a/ligature/OperatorMonoSSmLig-BookItalic/config.xml b/ligature/OperatorMonoSSmLig-BookItalic/config.xml
index 4f422d6..2499fb1 100644
--- a/ligature/OperatorMonoSSmLig-BookItalic/config.xml
+++ b/ligature/OperatorMonoSSmLig-BookItalic/config.xml
@@ -11,8 +11,6 @@
         <fontRevision value="1.002"/>
         
     
-        <checkSumAdjustment value="0x713ccd21"/>
-        
     
         <magicNumber value="0x5f0f3cf5"/>
         
@@ -23,11 +21,7 @@
         <unitsPerEm value="1000"/>
         
     
-        <created value="Wed Apr 17 14:51:42 2019"/>
-        
     
-        <modified value="Wed Apr 17 14:51:42 2019"/>
-        
     
         <xMin value="-1771"/>