diff --git a/Changelog.md b/Changelog.md
index 127b821..afffce7 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -10,6 +10,10 @@ Release template text:
 	```
 
 
+## v1.1.1
+ - Update `terrain50` to v1.4.1
+
+
 ## v1.1.0
  - Add support for `Terrain50.ParseStream()` via new --mode flag for the validator subcommand
 
diff --git a/package-lock.json b/package-lock.json
index 1c4ca22..66740c6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -279,9 +279,9 @@
 			"integrity": "sha512-NCrCHhWmnQklfH4MtJMRjZ2a8c80qXeMlQMv2uVp9ISJMTt562SbGd6n2oq0PaPgKm7Z6pL9E2UlLIhC+SHL3w=="
 		},
 		"proj4": {
-			"version": "2.6.1",
-			"resolved": "https://registry.npmjs.org/proj4/-/proj4-2.6.1.tgz",
-			"integrity": "sha512-RP5EcrfrLcARy+Zjjz1wIeqZzZdPtQNl685asHcwdU/MQ/dvydmf1XWM4mgok6wPaNsXZ8IFrM4qadO3g46PiQ==",
+			"version": "2.6.2",
+			"resolved": "https://registry.npmjs.org/proj4/-/proj4-2.6.2.tgz",
+			"integrity": "sha512-Pn0+HZtXb4JzuN8RR0VM7yyseegiYHbXkF+2FOdGpzRojcZ1BTjWxOh7qfp2vH0EyLu8pvcrhLxidwzgyUy/Gw==",
 			"requires": {
 				"mgrs": "1.0.0",
 				"wkt-parser": "^1.2.4"
@@ -338,9 +338,9 @@
 			}
 		},
 		"terrain50": {
-			"version": "1.4.0",
-			"resolved": "https://registry.npmjs.org/terrain50/-/terrain50-1.4.0.tgz",
-			"integrity": "sha512-N+2Im3s4LUhB5Atrsk7TKuJ7ty6maL3dz/jb+jAF48X4yK/YY6Fi4GSaCp2xx2+9F9YBMrzeJA6iDzQpMDr91A==",
+			"version": "1.4.1",
+			"resolved": "https://registry.npmjs.org/terrain50/-/terrain50-1.4.1.tgz",
+			"integrity": "sha512-U3zK3eLZr/rnLHdC9It+aCY6tgv86hwFSve+L43Fg9Pgg2BHebCWLBwa4PQWgwRGlUutwl8BRQzLCoCPu4sIag==",
 			"requires": {
 				"nexline": "^1.2.0",
 				"nnng": "^1.0.0"
diff --git a/package.json b/package.json
index 98dec02..299add1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "terrain50-cli",
-	"version": "1.1.0",
+	"version": "1.1.1",
 	"description": "CLI for parsing Ordnance Survey Digital Elevation Model files",
 	"main": "src/index.mjs",
 	"scripts": {
@@ -37,7 +37,7 @@
 		"chroma-js": "^2.1.0",
 		"image-encode": "^1.3.0",
 		"nexline": "^1.2.0",
-		"terrain50": "^1.4.0"
+		"terrain50": "^1.4.1"
 	},
 	"bin": {
 		"terrain50": "./src/index.mjs"