diff --git a/intf_.mod b/intf_.mod
index a0d8d28..a6e8f8c 100644
--- a/intf_.mod
+++ b/intf_.mod
@@ -19,7 +19,6 @@ ENDCOMMENT
 VERBATIM
 extern void* vector_arg();
 extern FILE* hoc_obj_file_arg(int narg);
-extern int list_vector_px(Object *ob, int i, double** px);
 extern int list_vector_px2 (Object *ob, int i, double** px, void** vv);
 extern Object** hoc_objgetarg();
 extern int ivoc_list_count(Object*);
@@ -184,7 +183,7 @@ CONSTRUCTOR {
     if (ifarg(1)) { lid=(int) *getarg(1); } else { lid= UINT_MAX; }
     if (ifarg(2)) { lty=(int) *getarg(2); } else { lty= -1; }
     if (ifarg(3)) { lco=(int) *getarg(3); } else { lco= -1; }
-    _p_sop = (void*)ecalloc(1, sizeof(id0));
+    _p_sop = (double*)ecalloc(1, sizeof(id0));
     ip = IDP;
     ip->id=lid; ip->type=lty; ip->col=lco; 
     ip->invl0 = ip->record = ip->jitter = ip->input = 0; // all flags off
@@ -541,7 +540,7 @@ PROCEDURE vers () {
 
 :** val(t,tstart) fills global vii[] to pass values back to record() (called from record())
 VERBATIM
-double val (double xx, double ta) { 
+void val(double xx, double ta) {
   vii[1]=VAM*EXP(-(xx - ta)/tauAM);
   vii[2]=VNM*EXP(-(xx - ta)/tauNM);
   vii[3]=VGA*EXP(-(xx - ta)/tauGA);
@@ -557,7 +556,7 @@ ENDVERBATIM
 
 :** valps(t,tstart) like val but builds voltages for pop spike
 VERBATIM
-double valps (double xx, double ta) { 
+void valps(double xx, double ta) {
   vii[1]=VAM*EXP(-(xx - ta)/tauAM);
   vii[2]=VNM*EXP(-(xx - ta)/tauNM);
   vii[3]=VGA*EXP(-(xx - ta)/tauGA);
@@ -572,11 +571,14 @@ PROCEDURE record () {
   VERBATIM {
   int k; double ti;
   vp = SOP;
-  if (tg>=t) return;
-  if (vp->p >= vp->size) { if (errflag) return; 
+  if (tg>=t) return 0;
+  if (vp->p >= vp->size) {
+    if (errflag) return 0;
     printf("**** WARNING out of recording room for INTF type%d id%d at %g****\n",IDP->type,IDP->id,t);
     printf("**************** WARNING: No further WARNINGS ****************\n");
-    errflag=1; return; }
+    errflag=1;
+    return 0;
+  }
   for (ti=tg;ti<=t && vp->p < vp->size;ti+=vdt,vp->p++) { 
     val(ti,tg);  
     vp->vvo[0][vp->p]=ti;
@@ -594,7 +596,9 @@ PROCEDURE recspk (x) {
   VERBATIM { int k;
   vp = SOP;
   record();
-  if (vp->p >= vp->size || vp->vvo[6]==0) return; 
+  if (vp->p >= vp->size || vp->vvo[6]==0) {
+    return 0;
+  }
   vp->vvo[0][vp->p-1]=_lx;
   vp->vvo[6][vp->p-1]=spkht; // the spike
   tg=_lx;
@@ -677,11 +681,11 @@ PROCEDURE trvsp ()
 {
   VERBATIM 
   int i, flag; 
-  double ind, t0;
+  double ind, t0_local;
   ip=IDP;
   flag=(int) *getarg(1);
   if (subsvint==0.) {printf("trvsp"); return(0.);}
-  ind=isp[0]; t0=vsp[0];
+  ind=isp[0]; t0_local=vsp[0];
   if (flag==1) {
     for (i=0; i<vspn; i++) {
       if (isp[i]!=ind) {
@@ -693,11 +697,12 @@ PROCEDURE trvsp ()
   } else if (flag==2) {
     for (i=0; i<vspn; i++) {
       if (isp[i]!=ind) {
-        vsp[i-1]=t0+subsvint;
-        ind=isp[i]; t0=vsp[i];
+        vsp[i-1] = t0_local + subsvint;
+        ind = isp[i];
+        t0_local = vsp[i];
       }
     }
-    vsp[vspn-1]=t0+subsvint;
+    vsp[vspn-1] = t0_local + subsvint;
   } else {printf("trvsp flag %d not recognized\n",flag); hxe();}
   ENDVERBATIM
 }
@@ -1085,7 +1090,8 @@ PROCEDURE wrecord (te) {
     for (j= -max;j<=max && k+j>0 && k+j<wwsz;j++) {
       wwo[wrp][k+j] += scale*_t_Psk[j+max]; // direct copy from the Psk table
     }
-  } else if (twg>=t) { return;
+  } else if (twg>=t) {
+    return 0;
   } else {
     for (ti=twg,k=(int)floor((twg-rebeg)/vdt+0.5);ti<=t && k<wwsz;ti+=vdt,k++) { 
       valps(ti,twg);  // valps() for pop spike calculation
diff --git a/misc.mod b/misc.mod
index c346c00..e202303 100644
--- a/misc.mod
+++ b/misc.mod
@@ -47,6 +47,9 @@ VERBATIM
 #include <time.h>
 #include <stdio.h>
 #include <limits.h>
+#ifndef NRN_VERSION_GTEQ_8_2_0
+extern FILE* hoc_obj_file_arg(int narg);
+#endif
 ENDVERBATIM
 
 :* FUNCTION file_exist()
@@ -56,10 +59,7 @@ VERBATIM
        errno else will get a nrnoc error.  Seems to be a problem even
        if I don't include <errno.h> */
 
-    char *gargstr(), *filename;
-
-    filename = gargstr(1);
-
+    char* filename = gargstr(1);
     if (*filename && !access(filename, F_OK)) {
         _lfile_exist = 1;
 
@@ -77,19 +77,18 @@ PROCEDURE sassign() {
 VERBATIM
     FILE *pipein;
     char string[BUFSIZ], **strname, *syscall;
-    char** hoc_pgargstr();
-
     strname = hoc_pgargstr(1);
     syscall = gargstr(2);
 
     if( !(pipein = popen(syscall, "r"))) {
         fprintf(stderr,"System call failed\n");
-        return; 
+        return 0;
     }
     
     if (fgets(string,BUFSIZ,pipein) == NULL) {
         fprintf(stderr,"System call did not return a string\n");
-        pclose(pipein); return;
+        pclose(pipein);
+        return 0;
     }
 
     /*  assign_hoc_str(strname, string, 0); */
@@ -112,17 +111,20 @@ VERBATIM
 
     if ( !(outfile = fopen("dassign","w"))) {
         fprintf(stderr,"Can't open output file dassign\n");
-        return; 
+        return 0;
     }
 
     if( !(pipein = popen(syscall, "r"))) {
         fprintf(stderr,"System call failed\n");
-        fclose(outfile); return; 
+        fclose(outfile);
+        return 0;
     }
     
     if (fscanf(pipein,"%lf",&num) != 1) {
         fprintf(stderr,"System call did not return a number\n");
-        fclose(outfile); pclose(pipein); return; 
+        fclose(outfile);
+        pclose(pipein);
+        return 0;
     }
 
     fprintf(outfile,"%s=%g\n",strname,num);
@@ -176,8 +178,7 @@ ENDVERBATIM
 PROCEDURE fspitchar(c) {
 VERBATIM
 {	
-  FILE* f, *hoc_obj_file_arg();
-  f = hoc_obj_file_arg(2);
+  FILE* f = hoc_obj_file_arg(2);
   fprintf(f, "%c", (int)_lc);
 }
 ENDVERBATIM
@@ -223,8 +224,7 @@ ENDVERBATIM
 FUNCTION hocgetc() {
 VERBATIM
 {	
-  FILE* f, *hoc_obj_file_arg();
-  f = hoc_obj_file_arg(1);
+  FILE* f = hoc_obj_file_arg(1);
   _lhocgetc = (double)getc(f);
 }
 ENDVERBATIM
diff --git a/readme.html b/readme.html
index c627bfd..c4202b2 100644
--- a/readme.html
+++ b/readme.html
@@ -28,4 +28,9 @@
 
 in addition to the graph, a panel is launched that allows you to look
 at several other voltage traces that were recorded during the run
+
+Changelog
+---------
+2022-05: Updated MOD files to contain valid C++ and be compatible
+         with the upcoming versions 8.2 and 9.0 of NEURON.
 </pre></html>
diff --git a/stats.mod b/stats.mod
index 41b19dc..e29ca0a 100644
--- a/stats.mod
+++ b/stats.mod
@@ -31,7 +31,6 @@ ASSIGNED { }
 VERBATIM
 #include <stdlib.h>
 #include <math.h>
-#include <values.h> /* contains MAXLONG */
 #include <sys/time.h> 
 extern double BVBASE;
 extern double* hoc_pgetarg();
@@ -46,9 +45,6 @@ extern double hoc_epsilon;
 extern void set_seed();
 extern int ivoc_list_count(Object*);
 extern Object* ivoc_list_item(Object*, int);
-extern int list_vector_px2();
-int list_vector_px();
-int list_vector_resize();
 static void hxe() { hoc_execerror("",0); }
 
 typedef struct BVEC {
@@ -484,8 +480,6 @@ FUNCTION gammln (xx) {
 FUNCTION betai(a,b,x) {
 VERBATIM {
   double bt;
-  double gammln(),betacf();
-
   if (_lx < 0.0 || _lx > 1.0) {printf("Bad x in routine BETAI\n"); hxe();}
   if (_lx == 0.0 || _lx == 1.0) bt=0.0;
   else
diff --git a/vecst.mod b/vecst.mod
index f567b6d..5bc7839 100644
--- a/vecst.mod
+++ b/vecst.mod
@@ -91,9 +91,9 @@ PARAMETER {
 ASSIGNED { RES }
 
 VERBATIM
+#ifndef NRN_VERSION_GTEQ_8_2_0
 #include <stdlib.h>
 #include <math.h>
-#include <values.h> // contains MAXLONG 
 #include <sys/time.h> 
 extern double* hoc_pgetarg();
 extern double hoc_call_func(Symbol*, int narg);
@@ -111,10 +111,11 @@ extern Object* ivoc_list_item(Object*, int);
 extern int hoc_is_double_arg(int narg);
 extern char* hoc_object_name(Object*);
 char ** hoc_pgargstr();
-static int ismono1();
-int list_vector_px();
-int list_vector_px2();
-int list_vector_resize();
+#endif
+static int ismono1 (double *x, int n, int flag);
+int list_vector_px(Object *ob, int i, double** px);
+int list_vector_px2 (Object *ob, int i, double** px, void** vv);
+int list_vector_resize (Object *ob, int i, int sz);
 static double sc[6];
 static void hxe() { hoc_execerror("",0); }
 
@@ -147,6 +148,7 @@ static double ident(void* vv) {
   nx = vector_instance_px(vv, &x);
   bsz=vector_buffer_size(vv);
   printf("Obj*%x Dbl*%x Size: %d Bufsize: %d\n",vv,x,nx,bsz);
+  return 0.0;
 }
 ENDVERBATIM
  
@@ -495,8 +497,7 @@ VERBATIM
 static double iwr(void* vv) {
   int i, j, nx;
   double *x;
-  FILE* f, *hoc_obj_file_arg();
-  f = hoc_obj_file_arg(1);
+  FILE* f = hoc_obj_file_arg(1);
   nx = vector_instance_px(vv, &x);
   if (nx>scrsz) { 
     if (scrsz>0) { free(scr); scr=(unsigned int *)NULL; }
@@ -515,8 +516,7 @@ VERBATIM
 static double ird(void* vv) {
   int i, j, nx, n;
   double *x;
-  FILE* f, *hoc_obj_file_arg();
-  f = hoc_obj_file_arg(1);
+  FILE* f = hoc_obj_file_arg(1);
   nx = vector_instance_px(vv, &x);
   fread(&n,sizeof(int),1,f);  // size
   if (n>scrsz) { 
@@ -544,7 +544,7 @@ VERBATIM
 static double fread2(void* vv) {
   int i, j, nx, n, type, maxsz;
   double *x;
-  FILE* fp, *hoc_obj_file_arg();
+  FILE* fp;
   BYTEHEADER
 
   fp = hoc_obj_file_arg(1);
@@ -583,6 +583,7 @@ static double fread2(void* vv) {
     }
     free((char *)xf);    
   } else hoc_execerror("Type unsupported in fread2 ", 0);
+  return 0.0;
 }
 ENDVERBATIM
 
@@ -615,6 +616,7 @@ static double vfill (void* vv) {
 	nx = vector_instance_px(vv, &x);
 	nv1 = vector_arg_px(1, &v1);
         for (i=0;i<nx;i++) x[i]=v1[i%nv1];
+  return 0.0;
 }
 ENDVERBATIM
 
@@ -799,6 +801,7 @@ static double vscl(double *x, double n) {
   r=max-min;  // range
   sf = (b-a)/r; // scaling factor
   for (i=0;i<n;i++) x[i]=(x[i]-min)*sf+a;
+  return 0.0;
 }
 ENDVERBATIM
 
@@ -812,6 +815,7 @@ static double scl(void* vv) {
   if (nx!=nsrc) { hoc_execerror("scl:Vectors not same size: ", 0); }
   for (i=0;i<nx;i++) x[i]=src[i];
   vscl(x,nx);
+  return 0.0;
 }
 ENDVERBATIM
 
@@ -834,6 +838,7 @@ static double sccvlv(void* vv) {
     vscl(tmp,j-1);
     for (k=0;k<j;k++) x[i]+=filt[k]*tmp[k];
   }
+  return 0.0;
 }
 ENDVERBATIM
 
@@ -890,6 +895,7 @@ static double cvlv (void* vv) {
       if (k>0 && k<nsrc-1) x[i]+=filt[j]*src[k];
     }
   }
+  return 0.0;
 }
 ENDVERBATIM
 
@@ -987,7 +993,7 @@ static double keyind(void* vv) {
   int i, j, k, ni, nk, nv[VRRY], num;
   double *ind, *key, *vvo[VRRY];
   ni = vector_instance_px(vv, &ind); // vv is ind
-  for (i=0;ifarg(i);i++); i--; // drop back by one to get numarg()
+  for (i=0;ifarg(i);i++) {} i--; // drop back by one to get numarg()
   if (i>VRRY) hoc_execerror("ERR: keyind can only handle VRRY vectors", 0);
   num = i-1; // number of vectors to be picked apart 
   for (i=0;i<num;i++) { 
@@ -1087,6 +1093,7 @@ static double bpeval(void* vv) {
   } else {
     for (i=0;i<n;i++) vo[i]=outp[i]*(1.-1.*outp[i])*del[i];
   }
+  return 0.0;
 }
 ENDVERBATIM
  
@@ -2033,7 +2040,15 @@ FUNCTION isojt () {
   Object *ob1, *ob2;
   ob1 = *hoc_objgetarg(1); ob2 = *hoc_objgetarg(2);
   if (!ob1) if (!ob2) return 1; else return 0;
-  if (!ob2 || ob1->template != ob2->template) {
+#define ctemplate template
+#ifdef NRN_VERSION_GTEQ_8_2_0
+#if NRN_VERSION_GTEQ(9, 0, 0)
+#undef ctemplate
+#define ctemplate ctemplate
+#endif
+#endif
+  if (!ob2 || ob1->ctemplate != ob2->ctemplate) {
+#undef ctemplate
     return 0;
   }
   return 1;