diff --git a/AGENTS.md b/AGENTS.md
index 3268ff0..6bcd8e6 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -29,6 +29,8 @@ pnpm run dev
 
 ### Production build
 
+Use this when verifying changes.
+
 ```bash
 pnpm run build
 ```
diff --git a/manifest.json b/manifest.json
index 66397ac..95c5560 100644
--- a/manifest.json
+++ b/manifest.json
@@ -1,7 +1,7 @@
 {
 	"id": "come-down",
 	"name": "Come Down",
-	"version": "1.1.1-rc.1",
+	"version": "1.1.1",
 	"minAppVersion": "1.8.0",
 	"description": "Maintains a cache of your notes’ embedded external images.",
 	"author": "mntno",
diff --git a/src/Env.ts b/src/Env.ts
index 7000624..5ccd3a8 100644
--- a/src/Env.ts
+++ b/src/Env.ts
@@ -108,6 +108,7 @@ export const Env = {
 		SPACE: " ",
 		is: (value: unknown): value is string => typeof value === "string",
 		nonEmpty: (value: unknown): string | undefined => typeof value === "string" && value !== "" ? value : undefined,
+		isNonEmpty: (value: unknown): value is string => typeof value === "string" && value !== "",
 	} as const,
 
 	bool: {
diff --git a/src/cache/CacheManager.ts b/src/cache/CacheManager.ts
index 637bd19..ae61580 100644
--- a/src/cache/CacheManager.ts
+++ b/src/cache/CacheManager.ts
@@ -891,12 +891,15 @@ export class CacheManager {
 
 			const response = await requestUrl({ url: sourceUrl, method: 'GET', throw: false });
 			const headers = Url.normalizeHeaders(response.headers);
-			const contentType = headers[Url.RESPONSE_HEADER_LOWERCASE.contentType] ?? undefined;
-			const cacheControl = headers[Url.RESPONSE_HEADER_LOWERCASE.cacheControl] ?? undefined;
+			const contentType = headers[Url.RESPONSE_HEADER_LOWERCASE.contentType];
+			const cacheControl = headers[Url.RESPONSE_HEADER_LOWERCASE.cacheControl];
+			const etag = Url.parseETag(headers[Url.RESPONSE_HEADER_LOWERCASE.etag]);
+			const lastModifiedHeader = headers[Url.RESPONSE_HEADER_LOWERCASE.lastModified];
+			const lastModified = lastModifiedHeader !== undefined ? new Date(lastModifiedHeader).toISOString() : undefined;
 
 			//Env.log.cm(Env.dev.icon.CACHE_MANAGER, `CacheManager:download: Got response:\n\tcacheID: ${cacheKey}\n\t${response.status}\n\tcontentType: ${contentType}`);
 
-			if (cacheControl == Url.CACHE_CONTROL_LOWERCASE.noStore)
+			if (cacheControl === Url.CACHE_CONTROL_LOWERCASE.noStore)
 				throw new CacheError(`Caching not allowed on ${sourceUrl}.`, cacheKey);
 
 			if (response.status >= 400)
@@ -926,6 +929,8 @@ export class CacheManager {
 					d: nowDateString,
 					l: nowDateString,
 					cc: cacheControl,
+					et: etag !== null ? etag : undefined,
+					m: lastModified,
 				},
 				f: {
 					s: sourceUrl,
diff --git a/src/cache/CacheMetadata.ts b/src/cache/CacheMetadata.ts
index e5332d2..d567be7 100644
--- a/src/cache/CacheMetadata.ts
+++ b/src/cache/CacheMetadata.ts
@@ -75,9 +75,32 @@ export interface CacheMetadataTime {
   /** Download time */
   d: string;
 
-  /** Last accessed */
+  /**
+		* "Last time checked".
+		*
+		* Currently set to download time and never updated.
+		* @todo May be used to keep track of when the server was last checked for modified.
+		*/
   l: string;
 
   /** Value of the `Cache-Control` HTTP response header. */
   cc?: string;
+
+  /**
+		* Value of the `ETag` HTTP response header.
+		*
+		* In the HTTP spec (RFC 7232), an ETag must be wrapped in double quotes. But here they are not. Add them back when using the ETag in requests.
+		*
+		* @since 1.1.1
+		*/
+  et?: string;
+
+	/**
+		* Normalized value of the `Last-Modified` HTTP response header (ISO 8601).
+		*
+		* Converted from HTTP-date format to ISO for consistency. Convert back to UTC string when using in 'If-Modified-Since' headers.
+		*
+		* @since 1.1.1
+		*/
+  m?: string;
 }
diff --git a/src/utils/Url.ts b/src/utils/Url.ts
index d0ded46..bcc7cf2 100644
--- a/src/utils/Url.ts
+++ b/src/utils/Url.ts
@@ -10,6 +10,8 @@ export class Url {
 		contentLength: "Content-Length".toLowerCase(),
 		cacheControl: "Cache-Control".toLowerCase(),
 		expires: "Expires".toLowerCase(),
+		etag: "ETag".toLowerCase(),
+		lastModified: "Last-Modified".toLowerCase(),
 	} as const;
 
 	public static readonly CACHE_CONTROL_LOWERCASE = {
@@ -81,6 +83,40 @@ export class Url {
 		return url.startsWith("app://") || url.startsWith("capacitor://") || url.startsWith("file://");
 	}
 
+	/**
+		* Parses an ETag header value into a storage-friendly format.
+		* - `W/"abc"` -> `W/abc`
+		* - `"abc"` -> `abc`
+		* @param value The raw ETag header string.
+		* @returns The tag value stripped of quotes, with "W/" prefix preserved if present.
+		* @since 1.1.1
+		*/
+	public static parseETag(value: string | undefined): string | null {
+		if (!Env.str.isNonEmpty(value))
+			return null;
+
+		const match = value.match(/^(W\/)?"(.*)"$/);
+		if (match === null)
+			return null;
+
+		const prefix = match[1] !== undefined ? match[1] : Env.str.EMPTY;
+		const tag = match[2];
+		return `${prefix}${tag}`;
+	}
+
+	/**
+		* Converts a stored ETag back to a format suitable for HTTP headers.
+		* - `W/abc` -> `W/"abc"`
+		* - `abc` -> `"abc"`
+		* @param tag The stored ETag value.
+		* @since 1.1.1
+		*/
+	public static stringifyETag(tag: string): string | null {
+		if (Env.str.nonEmpty(tag) === undefined)
+			return null;
+		return tag.replace(/^(W\/)?(.*)$/, '$1"$2"');
+	}
+
 	public static trimBackslash(url: string): string {
 		return url.endsWith("/") ? url.slice(0, -1) : url;
 	}