diff --git a/src/update/PatchNotes.lua b/src/update/PatchNotes.lua
index 3288c4de..5fb503b0 100644
--- a/src/update/PatchNotes.lua
+++ b/src/update/PatchNotes.lua
@@ -16,6 +16,10 @@ PatchNotes.FILES = {
   "assets/PATCH_NOTES.md",
 }
 
+PatchNotes.CACHE_FILES = {
+  "updates/notes_cache.json",
+}
+
 PatchNotes.REPO_FILES = {
   "mobile/ios/app-repo.json",
 }
@@ -48,6 +52,29 @@ local function readPath(path)
   return nonempty(text) and text or nil
 end
 
+function PatchNotes.fromCache(engine)
+  for _, path in ipairs(PatchNotes.CACHE_FILES) do
+    local text = readPath(path)
+    if text then
+      local ok, doc = pcall(Json.decode, text)
+      if ok and type(doc) == "table" then
+        if engine and engine ~= "0.0.0-dev" then
+          if doc[engine] and nonempty(doc[engine]) then
+            return doc[engine], engine
+          end
+        else
+          for ver, notes in pairs(doc) do
+            if nonempty(notes) then
+              return notes, ver
+            end
+          end
+        end
+      end
+    end
+  end
+  return nil, nil
+end
+
 function PatchNotes.fromFile()
   for _, path in ipairs(PatchNotes.FILES) do
     local text = readPath(path)
@@ -88,6 +115,7 @@ function PatchNotes.fromRepo(engine)
             return row.notes, row.version
           end
         end
+        return nil, nil
       end
       return list[1].notes, list[1].version
     end
@@ -96,17 +124,24 @@ function PatchNotes.fromRepo(engine)
 end
 
 function PatchNotes.body(Check)
-  local notes, ver = PatchNotes.fromCheck(Check)
-  if notes then return notes, ver end
-  notes = PatchNotes.fromFile()
-  if notes then return notes, ver end
   local Version = require("src.core.Version")
   local engine = (Version and Version.engine) or "?"
+
+  local notes, ver = PatchNotes.fromCheck(Check)
+  if notes and (engine == "0.0.0-dev" or ver == engine or ver == nil) then
+    return notes, ver or engine
+  end
+
+  notes, ver = PatchNotes.fromCache(engine)
+  if notes then return notes, ver end
+
+  notes = PatchNotes.fromFile()
+  if notes then return notes, engine end
+
   notes, ver = PatchNotes.fromRepo(engine)
   if notes then return notes, ver end
-  return "No patch notes loaded yet for gen1recomp v" .. engine .. ".\n\n"
-    .. "They appear here after the launcher checks GitHub for the latest "
-    .. "release.", engine
+
+  return "Unable to fetch patch notes.", engine
 end
 
 return PatchNotes
diff --git a/src/update/check_worker.lua b/src/update/check_worker.lua
index 7d592ec6..175a5457 100644
--- a/src/update/check_worker.lua
+++ b/src/update/check_worker.lua
@@ -151,6 +151,28 @@ local function gatePasses(rel)
   return not (info.minShell and info.minShell > shell)
 end
 
+local function cacheNotes(ver, notes)
+  if not (ver and type(notes) == "string" and notes ~= "" and Json) then return end
+  if not (love and love.filesystem) then return end
+  pcall(function()
+    love.filesystem.createDirectory("updates")
+    local cachePath = "updates/notes_cache.json"
+    local existing = {}
+    if love.filesystem.getInfo and love.filesystem.getInfo(cachePath) then
+      local text = love.filesystem.read(cachePath)
+      if text then
+        local ok, doc = pcall(Json.decode, text)
+        if ok and type(doc) == "table" then existing = doc end
+      end
+    end
+    existing[ver] = notes
+    local ok, encoded = pcall(Json.encode, existing)
+    if ok and encoded then
+      love.filesystem.write(cachePath, encoded)
+    end
+  end)
+end
+
 -- ---------------------------------------------------------------------------
 -- check
 -- ---------------------------------------------------------------------------
@@ -177,6 +199,9 @@ local function doCheck()
     return
   end
   pending = rel
+  if rel.version and type(rel.notes) == "string" and rel.notes ~= "" then
+    cacheNotes(rel.version, rel.notes)
+  end
 
   -- Unstamped dev build: the working tree always looks "newer", so never
   -- pester the developer with an update (contract item, Check design).
diff --git a/tests/engine/launcher_patch_notes.lua b/tests/engine/launcher_patch_notes.lua
index 89fbc9c2..6532006f 100644
--- a/tests/engine/launcher_patch_notes.lua
+++ b/tests/engine/launcher_patch_notes.lua
@@ -68,6 +68,12 @@ do
     "stashed notes name a release version")
 end
 
+do
+  local notes, ver = PatchNotes.fromRepo("999.999.999")
+  eq(notes, nil, "fromRepo returns nil when a specific engine version is missing")
+  eq(ver, nil, "fromRepo version is nil when missing")
+end
+
 do
   local f = assert(io.open("mobile/ios/app-repo.json", "rb"))
   local list = PatchNotes.parseRepo(f:read("*a"))
@@ -78,6 +84,15 @@ do
   eq(notes, list[2].notes, "fromRepo returns that version's notes")
 end
 
+do
+  local oldVersion = package.loaded["src.core.Version"]
+  package.loaded["src.core.Version"] = { engine = "999.999.999" }
+  local body, ver = PatchNotes.body(nil)
+  eq(body, "Unable to fetch patch notes.", "returns Unable to fetch patch notes when version is uncached and unlisted")
+  eq(ver, "999.999.999", "returns the requested engine version")
+  package.loaded["src.core.Version"] = oldVersion
+end
+
 imp._appPatchNotes = true
 local modal = drawAndCapture(imp)
 check(modal:find("Patch notes", 1, true) ~= nil, "the modal titles itself")