diff --git a/src/core/desktopfile/desktopfilereader.cpp b/src/core/desktopfile/desktopfilereader.cpp
index 957eea5..7203ed2 100644
--- a/src/core/desktopfile/desktopfilereader.cpp
+++ b/src/core/desktopfile/desktopfilereader.cpp
@@ -95,8 +95,10 @@ namespace linuxdeploy {
                                         throw ParseError("Empty keys are not allowed");
 
                                     // keys may only contain A-Za-z- characters according to specification
-                                    for (const auto c : key) {
-                                        if (!(c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c == '-'))
+                                    for (const char c : key) {
+                                        if (!(
+                                                (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c == '-')
+                                            ))
                                             throw ParseError("Key contains invalid character " + std::string{c});
                                     }
 
diff --git a/tests/core/test_desktopfile_conformance.cpp b/tests/core/test_desktopfile_conformance.cpp
index 8f7529b..1b3107c 100644
--- a/tests/core/test_desktopfile_conformance.cpp
+++ b/tests/core/test_desktopfile_conformance.cpp
@@ -50,7 +50,7 @@ TEST_F(DesktopFileConformanceTest, testBasicFormatValidKeyCharacters) {
         ss << "[Desktop Entry]" << std::endl
            << "TestKey=foo" << std::endl;
 
-        EXPECT_THROW(DesktopFile file(ss), ParseError);
+        EXPECT_NO_THROW(DesktopFile file(ss));
     }
 
     {
@@ -58,7 +58,7 @@ TEST_F(DesktopFileConformanceTest, testBasicFormatValidKeyCharacters) {
         ss << "[Desktop Entry]" << std::endl
            << "4242trolol0=foo" << std::endl;
 
-        EXPECT_THROW(DesktopFile file(ss), ParseError);
+        EXPECT_NO_THROW(DesktopFile file(ss));
     }
 
     {
@@ -66,6 +66,14 @@ TEST_F(DesktopFileConformanceTest, testBasicFormatValidKeyCharacters) {
         ss << "[Desktop Entry]" << std::endl
            << "----=foo" << std::endl;
 
-        EXPECT_THROW(DesktopFile file(ss), ParseError);
+        EXPECT_NO_THROW(DesktopFile file(ss));
+    }
+
+    {
+        std::stringstream ss;
+        ss << "[Desktop Entry]" << std::endl
+           << "allLowerCase=foo" << std::endl;
+
+        EXPECT_NO_THROW(DesktopFile file(ss));
     }
 }