diff --git a/README.html b/README.html
index 93dd3f8..3305857 100644
--- a/README.html
+++ b/README.html
@@ -48,4 +48,7 @@
   produce traces in Fig 4 and data points for Figs. 6C and 8
 <p/><img src="./screenshot.png" alt="screenshot">
 </p>
+<p>
+<b>Changelog:</b><br>
+2022-05: Updated MOD files to contain valid C++ and be compatible with the upcoming versions 8.2 and 9.0 of NEURON.
 </html>
diff --git a/afhcsyn_i0.mod b/afhcsyn_i0.mod
index e919b66..e0bf486 100644
--- a/afhcsyn_i0.mod
+++ b/afhcsyn_i0.mod
@@ -8,7 +8,7 @@ ENDCOMMENT
 
 VERBATIM
 extern double du_dev0( );
-extern double dexp_dev( );
+extern double dexp_dev(double);
 ENDVERBATIM
 
 NEURON {
diff --git a/hc1.mod b/hc1.mod
index d85b15a..0ed63c9 100644
--- a/hc1.mod
+++ b/hc1.mod
@@ -7,8 +7,8 @@ Fires as Poisson process with rate constant tau
 ENDCOMMENT
 
 VERBATIM
-extern double du_dev0( );
-extern double dexp_dev( );
+double du_dev0();
+double dexp_dev(double);
 ENDVERBATIM
 
 NEURON {
diff --git a/random.mod b/random.mod
index 262fc93..f314388 100644
--- a/random.mod
+++ b/random.mod
@@ -36,7 +36,7 @@ extern double dexp_dev( double lambda );
 extern double dgauss_dev0();
 extern double dgauss_dev( double mean, double sdev );
 extern int igeom_dev( double pg );
-double ran2();	/* ran2 not to be used elsewhere */
+double ran2(long*);	/* ran2 not to be used elsewhere */
 
 ENDVERBATIM
 
diff --git a/ribbon1.mod b/ribbon1.mod
index 2f4e59b..c6b7523 100644
--- a/ribbon1.mod
+++ b/ribbon1.mod
@@ -7,10 +7,13 @@ alpha(t) = t/tau * exp( -t/tau )
 ENDCOMMENT
 
 VERBATIM
-extern double du_dev0( );
-extern double dexp_dev( );
+/* defined in random.mod */
+double du_dev0();
+double dexp_dev(double);
+int igeom_dev(double);
 ENDVERBATIM
 
+
 NEURON {
   POINT_PROCESS 	ribbon1
   RANGE 		i, del, xp, yp, zp, dist, tau, sw