diff --git a/ProbAMPANMDA2.mod b/ProbAMPANMDA2.mod
index 25c7377..b916d6c 100644
--- a/ProbAMPANMDA2.mod
+++ b/ProbAMPANMDA2.mod
@@ -47,8 +47,13 @@ VERBATIM
 #include<stdio.h>
 #include<math.h>
 
+#ifndef NRN_VERSION_GTEQ_8_2_0
 double nrn_random_pick(void* r);
 void* nrn_random_arg(int argpos);
+#define RANDCAST
+#else
+#define RANDCAST (Rand*)
+#endif
 
 ENDVERBATIM
   
@@ -185,7 +190,7 @@ VERBATIM
                 : each instance. However, the corresponding hoc Random
                 : distribution MUST be set to Random.negexp(1)
                 */
-                value = nrn_random_pick(_p_rng);
+                value = nrn_random_pick(RANDCAST _p_rng);
 		        //fi = fopen("RandomStreamMCellRan4.txt", "w");
                 //fprintf(fi,"random stream for this simulation = %lf\n",value);
                 //printf("random stream for this simulation = %lf\n",value);
diff --git a/ProbUDFsyn2.mod b/ProbUDFsyn2.mod
index 2807653..e2036c1 100644
--- a/ProbUDFsyn2.mod
+++ b/ProbUDFsyn2.mod
@@ -43,8 +43,13 @@ VERBATIM
 #include<stdio.h>
 #include<math.h>
 
+#ifndef NRN_VERSION_GTEQ_8_2_0
 double nrn_random_pick(void* r);
 void* nrn_random_arg(int argpos);
+#define RANDCAST
+#else
+#define RANDCAST (Rand*)
+#endif
 
 ENDVERBATIM
   
@@ -155,7 +160,7 @@ VERBATIM
                 : each instance. However, the corresponding hoc Random
                 : distribution MUST be set to Random.negexp(1)
                 */
-                value = nrn_random_pick(_p_rng);
+                value = nrn_random_pick(RANDCAST _p_rng);
 		        //fi = fopen("RandomStreamMCellRan4.txt", "w");
                 //fprintf(fi,"random stream for this simulation = %lf\n",value);
                 //printf("random stream for this simulation = %lf\n",value);
diff --git a/readme.txt b/readme.txt
index 011dee1..2c62f79 100644
--- a/readme.txt
+++ b/readme.txt
@@ -12,3 +12,8 @@ Parameters for the user to play with:
 2. connectivity = 0 or 1, whether the cells are interconnected or not
 3. modelnum = 1 to 6, referring to the different biophysical models
 4. condition = simulation condition, see comments in file for options
+
+Changelog
+---------
+2022-05: Updated MOD files to contain valid C++ and be compatible with
+         the upcoming versions 8.2 and 9.0 of NEURON.