diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,10 @@
 # Revision history for stack-all
 
+## 0.1.2 (2021-02-05)
+- --create-config comment line mentions older version
+- show error for unversioned "stack-lts.yaml"
+- add lts-17
+
 ## 0.1.1 (2020-12-04)
 - fix ordering of stack-lts-*.yaml
 - allow --newest to override oldest lts config
diff --git a/Main.hs b/Main.hs
--- a/Main.hs
+++ b/Main.hs
@@ -44,7 +44,7 @@
 defaultOldest = LTS 11
 
 allSnaps :: [Snapshot]
-allSnaps = [Nightly, LTS 16, LTS 14, LTS 13, LTS 12, LTS 11,
+allSnaps = [Nightly, LTS 17, LTS 16, LTS 14, LTS 13, LTS 12, LTS 11,
             LTS 10, LTS 9, LTS 8, LTS 6, LTS 5, LTS 4, LTS 2, LTS 1]
 
 data VersionSpec = DefaultVersions | Oldest Snapshot | AllVersions | VersionList [Snapshot]
@@ -90,6 +90,7 @@
     mapM_ (stackBuild configs debug mcmd) (newestFilter versions)
   where
     readStackConf :: FilePath -> Maybe Snapshot
+    readStackConf "stack-lts.yaml" = error' "unversioned stack-lts.yaml is unsupported"
     readStackConf f =
       stripPrefix "stack-" f >>= stripSuffix ".yaml" >>= readCompactSnap
 
@@ -101,8 +102,11 @@
   exists <- doesFileExist stackAllFile
   if exists then error' $ stackAllFile ++ " already exists"
     else do
+    let older =
+          let molder = listToMaybe $ dropWhile (>= snap) allSnaps
+          in maybe "" (\s -> showSnap s ++ " too old") molder
     writeFile stackAllFile $
-      "[versions]\n# reason comment\noldest = " ++ showSnap snap ++ "\n"
+      "[versions]\n# " ++ older ++ "\noldest = " ++ showSnap snap ++ "\n"
 
 readOldestLTS :: IO (Maybe Snapshot)
 readOldestLTS = do
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@
 `stack-all` runs `stack build` over recent Stackage LTS major versions
 and Nightly: by default currently: nightly, lts-16, ..., lts-11.
 
-Note that stack-all will automatically use `stack-ltsXX.yaml`, even for older lts releases: eg say you have `stack-lts13.yaml` in your project, then it will also be used for building lts-12 (unless you have a `stack-lts12.yaml` config file of course).
+Note that stack-all will automatically use `stack-ltsXX.yaml`, even for older lts releases: eg say you have `stack-lts13.yaml` in your project, then it will also be used for building lts-12 (unless you have a `stack-lts12.yaml` config file of course).  (Other versioned stack.yaml filenames like stack-ghc-8.8.yaml are not supported currently.)
 
 You can specify the oldest working LTS for a project with `stack-all -o lts-13` or set it in a `.stack-all` file containing:
 ```
diff --git a/stack-all.cabal b/stack-all.cabal
--- a/stack-all.cabal
+++ b/stack-all.cabal
@@ -1,5 +1,5 @@
 name:                stack-all
-version:             0.1.1
+version:             0.1.2
 synopsis:            CLI tool for building across Stackage major versions
 description:
         Build your Haskell project over Stackage major versions.
@@ -7,7 +7,7 @@
 license-file:        LICENSE
 author:              Jens Petersen <juhpetersen@gmail.com>
 maintainer:          Jens Petersen <juhpetersen@gmail.com>
-copyright:           2020  Jens Petersen <juhpetersen@gmail.com>
+copyright:           2020-2021  Jens Petersen <juhpetersen@gmail.com>
 category:            Distribution
 homepage:            https://github.com/juhp/stack-all
 bug-reports:         https://github.com/juhp/stack-all/issues
@@ -46,3 +46,5 @@
   if impl(ghc >= 8.4)
     ghc-options:       -Wmissing-export-lists
                        -Wpartial-fields
+  if impl(ghc >= 8.10)
+    ghc-options:       -Wunused-packages