diff --git a/Dockerfile b/Dockerfile
index 54b6cc33..11a6def2 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -32,6 +32,7 @@ COPY .git .git
 
 # Set UI version 
 RUN echo "export const VERSION = '$(git describe --tag)';" > "src/shared/version.ts"
+RUN echo "export const BUILD_DATE_ISO8601 = '$(date -d "+1 year" -u +"%Y-%m-%dT%H:%M:%SZ")';" > "src/shared/build-date.ts"
 
 RUN yarn --production --prefer-offline --network-timeout 100000
 RUN yarn build:prod
diff --git a/dev.dockerfile b/dev.dockerfile
index 42d12400..71aa6be6 100644
--- a/dev.dockerfile
+++ b/dev.dockerfile
@@ -24,6 +24,7 @@ COPY .git .git
 
 # Set UI version 
 RUN echo "export const VERSION = 'dev';" > "src/shared/version.ts"
+RUN echo "export const BUILD_DATE_ISO8601 = 'dev-build-date';" > "src/shared/build-date.ts"
 
 RUN yarn --prefer-offline
 RUN yarn build:dev
@@ -34,4 +35,4 @@ COPY --from=builder /usr/src/app/node_modules /app/node_modules
 
 EXPOSE 1234
 WORKDIR /app
-CMD node dist/js/server.js
\ No newline at end of file
+CMD node dist/js/server.js
diff --git a/src/server/handlers/security-handler.ts b/src/server/handlers/security-handler.ts
index 03fcf31a..b9b3bcdb 100644
--- a/src/server/handlers/security-handler.ts
+++ b/src/server/handlers/security-handler.ts
@@ -1,11 +1,12 @@
 import type { Response } from "express";
+import { BUILD_DATE_ISO8601 } from "../../shared/build-date";
 
 export default async ({ res }: { res: Response }) => {
   res.setHeader("content-type", "text/plain; charset=utf-8");
 
   res.send(
     `Contact: https://github.com/LemmyNet/lemmy-ui/security/advisories/new
-  Expires: 2025-01-01T04:59:00.000Z
+  Expires: ${BUILD_DATE_ISO8601}
   `,
   );
 };
diff --git a/src/shared/build-date.ts b/src/shared/build-date.ts
new file mode 100644
index 00000000..d0aa547a
--- /dev/null
+++ b/src/shared/build-date.ts
@@ -0,0 +1 @@
+export const BUILD_DATE_ISO8601 = "2025-01-19T16:08:27Z";