diff --git a/CImg.h b/CImg.h
index cbaa70df..71614018 100644
--- a/CImg.h
+++ b/CImg.h
@@ -21410,6 +21410,19 @@ namespace cimg_library {
                 return_comp = true;
                 _cimg_mp_return(pos);
               }
+
+              if (!std::strncmp(ss,"isvar(",6)) { // Is existing variable?
+                _cimg_mp_op("Function 'isvar()'");
+                if (ss6==se1) _cimg_mp_return(0);
+                s1 = ss6; while (s1<se && (*s1!=')' || level[s1 - expr._data]!=clevel)) ++s1; // Closing parenthesis
+                if (*s1!=')') _cimg_mp_return(0);
+                variable_name.assign(s1 - ss6 + 1);
+                if (variable_name._width) std::memcpy(variable_name,ss6,variable_name.width() - 1);
+                variable_name.back() = 0;
+                get_variable_pos(variable_name,arg1,arg2);
+                if (arg1!=~0U || arg2!=~0U) _cimg_mp_return(1);
+                _cimg_mp_return(0);
+              }
             }
             break;
 
@@ -23278,7 +23291,7 @@ namespace cimg_library {
                 if (arg1==11) { _cimg_mp_scalar0(is_sth?mp_rand_int_m1_1:mp_rand_double_m1_1); }
               } else if (!arg1) { _cimg_mp_scalar1(is_sth?mp_rand_int_0_N:mp_rand_double_0_N,arg2); }
               _cimg_mp_scalar2(op,arg1,arg2);
-            } else { // Slower version (open set)
+            } else { // Slower version (potentially an open set)
               op = is_sth?mp_rand_int_ext:mp_rand_double_ext;
               if (is_vector(arg1) && is_vector(arg2))
                 _cimg_mp_vector4_vvss(op,arg1,arg2,arg3,arg4);
@@ -28938,8 +28951,8 @@ namespace cimg_library {
           _M = _mp_arg(3);
         if (_m>_M) cimg::swap(_m,_M);
         const double
-          m = cimg::type<cimg_uint64>::cut(std::ceil(_m)),
-          M = cimg::type<cimg_uint64>::cut(std::floor(_M));
+          m = cimg::type<cimg_int64>::cut(std::ceil(_m)),
+          M = cimg::type<cimg_int64>::cut(std::floor(_M));
         return (double)m + _mp_rand_int(mp,M - m);
       }
 
@@ -28960,7 +28973,7 @@ namespace cimg_library {
         return val<th?-1:val<2*th?0:1;
       }
 
-      static double mp_rand_int_ext(_cimg_math_parser& mp) { // Integer version of mp_rand_u_ext
+      static double mp_rand_int_ext(_cimg_math_parser& mp) {
         const bool
           include_min = (bool)_mp_arg(4),
           include_max = (bool)_mp_arg(5);
diff --git a/html/header.html b/html/header.html
index a63fa8f6..a60c02eb 100644
--- a/html/header.html
+++ b/html/header.html
@@ -23,7 +23,7 @@
     <div class="header">
 <a href="index.html"><img alt="Logo" src="img/logo_header.jpg" class="center_image" style="margin-top:1em;"/></a>
       <h2  style="padding-bottom: 1em">
-        Latest stable version: <b><a href="http://cimg.eu/files/CImg_.zip">3.5.0</a></b> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Current pre-release: <b><a href="http://cimg.eu/files/CImg_latest.zip">3.5.1</a></b> (2025/01/19)
+        Latest stable version: <b><a href="http://cimg.eu/files/CImg_.zip">3.5.0</a></b> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Current pre-release: <b><a href="http://cimg.eu/files/CImg_latest.zip">3.5.1</a></b> (2025/01/22)
       </h2>
 
       <hr/>
diff --git a/html/header_doxygen.html b/html/header_doxygen.html
index de936e60..72ff9c84 100644
--- a/html/header_doxygen.html
+++ b/html/header_doxygen.html
@@ -26,7 +26,7 @@
     <div class="header">
 <a href="../index.html"><img alt="Logo" src="../img/logo_header.jpg" class="center_image" style="margin-top:1em;"/></a>
       <h2  style="padding-bottom: 1em">
-        Latest stable version: <b><a href="http://cimg.eu/files/CImg_.zip">3.5.0</a></b> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Current pre-release: <b><a href="http://cimg.eu/files/CImg_latest.zip">3.5.1</a></b> (2025/01/19)
+        Latest stable version: <b><a href="http://cimg.eu/files/CImg_.zip">3.5.0</a></b> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Current pre-release: <b><a href="http://cimg.eu/files/CImg_latest.zip">3.5.1</a></b> (2025/01/22)
       </h2>
 
       <hr/>