diff --git a/src/github.ts b/src/github.ts
index eaf3a70..b22ad86 100644
--- a/src/github.ts
+++ b/src/github.ts
@@ -44,7 +44,7 @@ export interface Releaser {
     target_commitish: string | undefined;
     discussion_category_name: string | undefined;
     generate_release_notes: boolean | undefined;
-    make_latest: string | undefined;
+    make_latest: "true" | "false" | "legacy" | undefined;
   }): Promise<{ data: Release }>;
 
   updateRelease(params: {
@@ -59,7 +59,7 @@ export interface Releaser {
     prerelease: boolean | undefined;
     discussion_category_name: string | undefined;
     generate_release_notes: boolean | undefined;
-    make_latest: string | undefined;
+    make_latest: "true" | "false" | "legacy" | undefined;
   }): Promise<{ data: Release }>;
 
   allReleases(params: {
@@ -93,8 +93,13 @@ export class GitHubReleaser implements Releaser {
     target_commitish: string | undefined;
     discussion_category_name: string | undefined;
     generate_release_notes: boolean | undefined;
-    make_latest: string | undefined;
+    make_latest: "true" | "false" | "legacy" | undefined;
   }): Promise<{ data: Release }> {
+
+    if (typeof params.make_latest === 'string' && !["true", "false", "legacy"].includes(params.make_latest)) {
+      params.make_latest = undefined;
+    }
+
     return this.github.rest.repos.createRelease(params);
   }
 
@@ -110,8 +115,13 @@ export class GitHubReleaser implements Releaser {
     prerelease: boolean | undefined;
     discussion_category_name: string | undefined;
     generate_release_notes: boolean | undefined;
-    make_latest: string | undefined;
+    make_latest: "true" | "false" | "legacy" | undefined;
   }): Promise<{ data: Release }> {
+
+    if (typeof params.make_latest === 'string' && !["true", "false", "legacy"].includes(params.make_latest)) {
+      params.make_latest = undefined;
+    }
+
     return this.github.rest.repos.updateRelease(params);
   }
 
diff --git a/src/util.ts b/src/util.ts
index 5dce79f..b12a4d0 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -19,7 +19,7 @@ export interface Config {
   input_discussion_category_name?: string;
   input_generate_release_notes?: boolean;
   input_append_body?: boolean;
-  input_make_latest: string | undefined;
+  input_make_latest: "true" | "false" | "legacy" | undefined;
 }
 
 export const uploadUrl = (url: string): string => {
@@ -71,12 +71,19 @@ export const parseConfig = (env: Env): Config => {
       env.INPUT_DISCUSSION_CATEGORY_NAME || undefined,
     input_generate_release_notes: env.INPUT_GENERATE_RELEASE_NOTES == "true",
     input_append_body: env.INPUT_APPEND_BODY == "true",
-    input_make_latest: env.INPUT_MAKE_LATEST
-      ? env.INPUT_MAKE_LATEST
-      : undefined,
+    input_make_latest: parseMakeLatest(env.INPUT_MAKE_LATEST),
   };
 };
 
+const parseMakeLatest = (
+  value: string | undefined
+): "true" | "false" | "legacy" | undefined => {
+  if (value === "true" || value === "false" || value === "legacy") {
+    return value;
+  }
+  return undefined;
+}
+
 export const paths = (patterns: string[]): string[] => {
   return patterns.reduce((acc: string[], pattern: string): string[] => {
     return acc.concat(