diff --git a/src/conf.h b/src/conf.h
index e2b3c559..e50b2505 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -741,8 +741,8 @@ unsigned membuffer_get_size(MemBuffer &mb);
 
 // util/dt_check.cpp
 void upx_compiler_sanity_check();
-bool upx_doctest_check();
-bool upx_doctest_check(int argc, char **argv);
+int upx_doctest_check();
+int upx_doctest_check(int argc, char **argv);
 
 // main.cpp
 extern const char *progname;
diff --git a/src/help.cpp b/src/help.cpp
index f56e0114..5e5603e6 100644
--- a/src/help.cpp
+++ b/src/help.cpp
@@ -407,6 +407,9 @@ void show_version(bool one_line)
     v = upx_lzma_version_string();
     if (v != nullptr && v[0])
         fprintf(fp, "LZMA SDK version %s\n", v);
+#endif
+#if !defined(DOCTEST_CONFIG_DISABLE)
+    fprintf(fp, "doctest C++ testing framework version %s\n", DOCTEST_VERSION_STR);
 #endif
     fprintf(fp, "Copyright (C) 1996-2022 Markus Franz Xaver Johannes Oberhumer\n");
     fprintf(fp, "Copyright (C) 1996-2022 Laszlo Molnar\n");
@@ -417,6 +420,9 @@ void show_version(bool one_line)
 #endif
 #if (WITH_LZMA)
     fprintf(fp, "Copyright (C) 1999" "-2006 Igor Pavlov\n");
+#endif
+#if !defined(DOCTEST_CONFIG_DISABLE)
+    fprintf(fp, "Copyright (C) 2016" "-2021 Viktor Kirilov\n");
 #endif
     fprintf(fp, "UPX comes with ABSOLUTELY NO WARRANTY; for details type '%s -L'.\n", progname);
 }
diff --git a/src/main.cpp b/src/main.cpp
index 98fe7482..ae57c831 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1159,8 +1159,12 @@ int upx_main(int argc, char *argv[]) {
     argv0 = argv[0];
 
     upx_compiler_sanity_check();
-    if (!upx_doctest_check(argc, argv)) {
-        fprintf(stderr, "%s: internal error: doctest failed\n", argv0);
+    int dt_res = upx_doctest_check(argc, argv);
+    if (dt_res != 0) {
+        if (dt_res == 2)
+            fprintf(stderr, "%s: doctest requested program exit; Stop.\n", argv0);
+        else
+            fprintf(stderr, "%s: internal error: doctest failed\n", argv0);
         e_exit(EXIT_INIT);
     }
 
diff --git a/src/util/dt_check.cpp b/src/util/dt_check.cpp
index 577b8d43..60b46257 100644
--- a/src/util/dt_check.cpp
+++ b/src/util/dt_check.cpp
@@ -31,14 +31,14 @@
 // upx_doctest_check()
 **************************************************************************/
 
-bool upx_doctest_check(int argc, char **argv) {
+int upx_doctest_check(int argc, char **argv) {
 #if defined(DOCTEST_CONFIG_DISABLE)
     UNUSED(argc);
     UNUSED(argv);
 #else
     const char *e = getenv("UPX_DEBUG_DOCTEST_DISABLE");
     if (e && e[0] && strcmp(e, "0") != 0)
-        return true;
+        return 0;
     bool minimal = true;   // only show failing tests
     bool duration = false; // show timings
     bool success = false;  // show all tests
@@ -68,13 +68,15 @@ bool upx_doctest_check(int argc, char **argv) {
     if (argc > 0 && argv != nullptr)
         context.applyCommandLine(argc, argv);
     int r = context.run();
-    if (context.shouldExit() || r != 0)
-        return false;
+    if (r != 0)
+        return 1;
+    if (context.shouldExit())
+        return 2;
 #endif // DOCTEST_CONFIG_DISABLE
-    return true;
+    return 0;
 }
 
-bool upx_doctest_check() { return upx_doctest_check(0, nullptr); }
+int upx_doctest_check() { return upx_doctest_check(0, nullptr); }
 
 /*************************************************************************
 // compile-time checks