diff --git a/src/libse/SubtitleFormats/SubRip.cs b/src/libse/SubtitleFormats/SubRip.cs
index e1c33d2390..f593fa01a7 100644
--- a/src/libse/SubtitleFormats/SubRip.cs
+++ b/src/libse/SubtitleFormats/SubRip.cs
@@ -291,7 +291,7 @@ private static string RemoveBadChars(string line)
         private bool TryReadTimeCodesLine(string input, Paragraph paragraph, bool validate)
         {
             var s = input.TrimStart('-', ' ');
-            if (s.Length < 10 || !char.IsDigit(s[0]))
+            if (s.Length < 10 || !CharUtils.IsDigit(s[0]))
             {
                 return false;
             }
@@ -428,7 +428,7 @@ private static bool IsValidTimeCode(string line)
 
                 if (step == 0 || step == 2 || step == 4 || step == 9 || step == 11) // start numbers
                 {
-                    if (ch == '-' || char.IsDigit(ch))
+                    if (ch == '-' || CharUtils.IsDigit(ch))
                     {
                         step++;
                     }
@@ -439,7 +439,7 @@ private static bool IsValidTimeCode(string line)
                 }
                 else if (step == 1 || step == 3 || step == 10 || step == 12) // number
                 {
-                    if (char.IsDigit(ch))
+                    if (CharUtils.IsDigit(ch))
                     {
                         // ok
                     }
@@ -454,7 +454,7 @@ private static bool IsValidTimeCode(string line)
                 }
                 else if (step == 5 || step == 13) // seconds
                 {
-                    if (char.IsDigit(ch))
+                    if (CharUtils.IsDigit(ch))
                     {
                         // ok
                     }
@@ -469,7 +469,7 @@ private static bool IsValidTimeCode(string line)
                 }
                 else if (step == 6 || step == 14) // milliseconds
                 {
-                    if (char.IsDigit(ch))
+                    if (CharUtils.IsDigit(ch))
                     {
                         // ok
                     }