diff --git a/CHANGELOG.md b/CHANGELOG.md
index cc8cb95..99ed870 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.1.0
+
+ - Update for null-safety support.
+
 ## 1.0.3
 
  - Allow user to specify placeholder character for nulla/zero.
diff --git a/analysis_options.yaml b/analysis_options.yaml
index a686c1b..c8b13e2 100644
--- a/analysis_options.yaml
+++ b/analysis_options.yaml
@@ -1,7 +1,7 @@
 # Defines a default set of lint rules enforced for
 # projects at Google. For details and rationale,
 # see https://github.com/dart-lang/pedantic#enabled-lints.
-include: package:pedantic/analysis_options.yaml
+include: package:pedantic/analysis_options.1.9.0.yaml
 
 # For lint rules and documentation, see http://dart-lang.github.io/linter/lints.
 # Uncomment to specify additional rules.
diff --git a/lib/src/int_extension.dart b/lib/src/int_extension.dart
index c2d570c..c17e3f4 100644
--- a/lib/src/int_extension.dart
+++ b/lib/src/int_extension.dart
@@ -15,11 +15,15 @@ final _romanNumbersToLetters = {
 };
 
 extension RomanNumeralsInt on int {
+  /// Check for a valid Roman numeral value -- this is a sanity check, as we
+  /// don't want 64k worth of M's.
+  bool get isValidRomanNumeralValue => !(this < 0 || this > 65535);
+
   /// Uses [nulla] as placeholder for zero. [nulla] should be a single, Roman,
   /// alphanumeric character.
-  String toRomanNumeralString({String nulla = 'N'}) {
+  String? toRomanNumeralString({String nulla = 'N'}) {
     // self-imposed maxium value. We don't need >64k worth of M's.
-    if (this < 0 || this > 65535) {
+    if (!isValidRomanNumeralValue) {
       return null;
     }
 
diff --git a/lib/src/string_extension.dart b/lib/src/string_extension.dart
index a5feed9..259bb91 100644
--- a/lib/src/string_extension.dart
+++ b/lib/src/string_extension.dart
@@ -29,7 +29,7 @@ extension RomanNumeralsString on String {
     return matches.length == 1;
   }
 
-  int toRomanNumeralValue() {
+  int? toRomanNumeralValue() {
     // Guard against malformed string sequences, and return early if the string itself is invalid
     if (!isValidRomanNumeral()) {
       return null;
diff --git a/pubspec.yaml b/pubspec.yaml
index 5cd9012..a90b943 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,15 +1,12 @@
 name: numerus
 description: Dart extensions for translating integers to Roman numerals and Roman numerals strings to integers.
-version: 1.0.3
+version: 1.1.0
 homepage: https://github.com/greymouser/dart-numerus
 
 environment:
-  sdk: '>=2.7.0 <3.0.0'
-
-#dependencies:
-#  path: ^1.6.0
+  sdk: '>=2.12.0-0 <3.0.0'
 
 dev_dependencies:
-  pedantic: ^1.8.0
-  test: ^1.6.0
-  test_coverage: ^0.4.1
+  pedantic: ^1.9.2
+  test: ^1.16.0-nullsafety.12
+  test_coverage: ^0.5.0
diff --git a/test/numerus_test.dart b/test/numerus_test.dart
index cf04156..cf9edd7 100644
--- a/test/numerus_test.dart
+++ b/test/numerus_test.dart
@@ -26,9 +26,9 @@ void main() {
     test('number to max unsigned long', () {
       var n = 65535;
       var got = n.toRomanNumeralString();
-      expect(got.length, 70); // the length of the insanely long string
-      expect(got[0], 'M');
-      expect(got.endsWith('MDXXXV'), true);
+      expect(got?.length, 70); // the length of the insanely long string
+      expect(got?[0], 'M');
+      expect(got?.endsWith('MDXXXV'), true);
     });
 
     test('number to greater than max unsigned long', () {