diff --git a/ChangeLog b/ChangeLog
index cae9d99e..9a74016e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,4 @@
-Version 2.15.0.9 (dev) not released yet (2025-03-09)
+Version 2.15.0.9 (dev) not released yet (2025-03-18)
 ====================================================
 
 **Incompatible changes**
@@ -26,6 +26,7 @@ Bugs
 ----
 - AZTEC: fix GS1 mode with Structured Append (wasn't outputting initial FNC1)
 - set_height: fix non-compliance false positives by using epsilon in checks
+- UPU_S10: fix Service Indicator warning re "H" (ticket #331, props Milton Neal)
 - manual/man page: fix DATAMATRIX Sizes tables "28 12x26" -> "27 12x26"
 
 
diff --git a/backend/code128_based.c b/backend/code128_based.c
index b86b078d..e628d645 100644
--- a/backend/code128_based.c
+++ b/backend/code128_based.c
@@ -273,14 +273,15 @@ INTERNAL int upu_s10(struct zint_symbol *symbol, unsigned char source[], int len
 
     /* Do some checks on the Service Indicator (first char only) and Country Code */
     if (strchr("JKSTW", local_source[0]) != NULL) { /* These are reserved & cannot be assigned */
-        error_number = errtxt(ZINT_WARN_NONCOMPLIANT, symbol, 839,
-                                "Invalid Service Indicator (first character should not be any of \"JKSTW\")");
-    } else if (strchr("FHIOXY", local_source[0]) != NULL) { /* These aren't allocated as of spec Oct 2017 */
-        error_number = errtxt(ZINT_WARN_NONCOMPLIANT, symbol, 840,
-                                "Non-standard Service Indicator (first 2 characters)");
+        error_number = errtxtf(ZINT_WARN_NONCOMPLIANT, symbol, 839,
+                                "Invalid Service Indicator '%.2s' (first character should not be any of \"JKSTW\")",
+                                local_source);
+    } else if (strchr("FIOXY", local_source[0]) != NULL) { /* These aren't allocated as of spec Oct 2017 */
+        error_number = errtxtf(ZINT_WARN_NONCOMPLIANT, symbol, 840,
+                                "Non-standard Service Indicator '%.2s' (first 2 characters)", local_source);
     } else if (!gs1_iso3166_alpha2(local_source + 11)) {
-        error_number = errtxt(ZINT_WARN_NONCOMPLIANT, symbol, 841,
-                                "Country code (last two characters) is not ISO 3166-1");
+        error_number = errtxtf(ZINT_WARN_NONCOMPLIANT, symbol, 841,
+                                "Country Code '%.2s' (last two characters) is not ISO 3166-1", local_source + 11);
     }
 
     (void) code128(symbol, local_source, 13); /* Only error returned is for large text which can't happen */
diff --git a/backend/tests/test_code128.c b/backend/tests/test_code128.c
index 9122e1dc..ca8cece7 100644
--- a/backend/tests/test_code128.c
+++ b/backend/tests/test_code128.c
@@ -1132,11 +1132,21 @@ static void test_upu_s10_input(const testCtx *const p_ctx) {
         /* 12*/ { "AB123456789A2", ZINT_ERROR_INVALID_DATA, 0, "Error 837: Invalid character in Country Code (last 2 characters) (alphabetic only)", "" },
         /* 13*/ { "AB12345678A2", ZINT_ERROR_INVALID_DATA, 0, "Error 837: Invalid character in Country Code (last 2 characters) (alphabetic only)", "" },
         /* 14*/ { "AB123456789AB", ZINT_ERROR_INVALID_CHECK, 0, "Error 838: Invalid check digit '9', expecting '5'", "" },
-        /* 15*/ { "JB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 839: Invalid Service Indicator (first character should not be any of \"JKSTW\")", "" },
-        /* 16*/ { "FB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 840: Non-standard Service Indicator (first 2 characters)", "" },
-        /* 17*/ { "AB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 841: Country code (last two characters) is not ISO 3166-1", "" },
-        /* 18*/ { "AB123100000IE", 0, 156, "", "Check digit 10 -> 0" },
-        /* 19*/ { "AB000000005IE", 0, 156, "", "Check digit 11 -> 5" },
+        /* 15*/ { "JB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 839: Invalid Service Indicator 'JB' (first character should not be any of \"JKSTW\")", "" },
+        /* 16*/ { "KB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 839: Invalid Service Indicator 'KB' (first character should not be any of \"JKSTW\")", "" },
+        /* 17*/ { "LB123456785AD", 0, 156, "", "" },
+        /* 18*/ { "SB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 839: Invalid Service Indicator 'SB' (first character should not be any of \"JKSTW\")", "" },
+        /* 19*/ { "TB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 839: Invalid Service Indicator 'TB' (first character should not be any of \"JKSTW\")", "" },
+        /* 20*/ { "WB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 839: Invalid Service Indicator 'WB' (first character should not be any of \"JKSTW\")", "" },
+        /* 21*/ { "FB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 840: Non-standard Service Indicator 'FB' (first 2 characters)", "" },
+        /* 22*/ { "HB123456785AD", 0, 156, "", "" },
+        /* 23*/ { "IB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 840: Non-standard Service Indicator 'IB' (first 2 characters)", "" },
+        /* 24*/ { "OB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 840: Non-standard Service Indicator 'OB' (first 2 characters)", "" },
+        /* 25*/ { "XB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 840: Non-standard Service Indicator 'XB' (first 2 characters)", "" },
+        /* 26*/ { "YB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 840: Non-standard Service Indicator 'YB' (first 2 characters)", "" },
+        /* 27*/ { "AB123456785AB", ZINT_WARN_NONCOMPLIANT, 156, "Warning 841: Country Code 'AB' (last two characters) is not ISO 3166-1", "" },
+        /* 28*/ { "AB123100000IE", 0, 156, "", "Check digit 10 -> 0" },
+        /* 29*/ { "AB000000005IE", 0, 156, "", "Check digit 11 -> 5" },
     };
     const int data_size = ARRAY_SIZE(data);
     int i, length, ret;