diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index e385c037..52c02c7b 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -408,7 +408,7 @@ class HttpCli(object):
             self.out_headers.update(NO_CACHE)
             return
 
-        n = "604800" if cache == "i" else cache or "69"
+        n = "604869" if cache == "i" else cache or "69"
         self.out_headers["Cache-Control"] = "max-age=" + n
 
     def k304(self) -> bool:
@@ -1714,7 +1714,7 @@ class HttpCli(object):
         # send reply
 
         if is_compressed:
-            self.out_headers["Cache-Control"] = "max-age=573"
+            self.out_headers["Cache-Control"] = "max-age=604869"
         else:
             self.permit_caching()
 
diff --git a/copyparty/web/up2k.js b/copyparty/web/up2k.js
index a9b619af..1887490d 100644
--- a/copyparty/web/up2k.js
+++ b/copyparty/web/up2k.js
@@ -719,12 +719,10 @@ function up2k_init(subtle) {
         "gotallfiles": [gotallfiles]  // hooks
     };
 
-    if (window.WebAssembly) {
-        for (var a = 0; a < Math.min(navigator.hardwareConcurrency || 4, 16); a++)
-            hws.push(new Worker('/.cpr/w.hash.js'));
-
-        console.log(hws.length + " hashers ready");
-    }
+    setTimeout(function () {
+        if (window.WebAssembly && !hws.length)
+            fetch('/.cpr/w.hash.js' + CB);
+    }, 1000);
 
     function showmodal(msg) {
         ebi('u2notbtn').innerHTML = msg;
@@ -1188,6 +1186,13 @@ function up2k_init(subtle) {
         var evpath = get_evpath(),
             draw_each = good_files.length < 50;
 
+        if (window.WebAssembly && !hws.length) {
+            for (var a = 0; a < Math.min(navigator.hardwareConcurrency || 4, 16); a++)
+                hws.push(new Worker('/.cpr/w.hash.js' + CB));
+
+            console.log(hws.length + " hashers");
+        }
+
         if (!uc.az)
             good_files.sort(function (a, b) {
                 a = a[0].size;
diff --git a/copyparty/web/util.js b/copyparty/web/util.js
index 32242446..31401c1c 100644
--- a/copyparty/web/util.js
+++ b/copyparty/web/util.js
@@ -7,6 +7,7 @@ if (!window['console'])
 
 
 var wah = '',
+    CB = '?_=' + Date.now(),
     HALFMAX = 8192 * 8192 * 8192 * 8192,
     HTTPS = (window.location + '').indexOf('https:') === 0,
     TOUCH = 'ontouchstart' in window,
@@ -15,8 +16,9 @@ var wah = '',
     IPHONE = TOUCH && /iPhone|iPad|iPod/i.test(navigator.userAgent),
     WINDOWS = navigator.platform ? navigator.platform == 'Win32' : /Windows/.test(navigator.userAgent);
 
-
 try {
+    CB = '?' + document.currentScript.src.split('?').pop();
+
     if (navigator.userAgentData.mobile)
         MOBILE = true;