diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..cc27a2a
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,3 @@
+# this tells Github to hide (collapse by default) generated files in diffs & PRs
+stack.yaml.lock linguist-generated=true
+
diff --git a/stack.yaml b/stack.yaml
index 7e63d99..2479e09 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,6 +1,12 @@
+resolver: lts-20.26
 flags:
   keter: {}
 packages:
 - '.'
-extra-deps: []
-resolver: lts-20
+extra-deps:
+  # pull newer from hackage; tar 0.6+ is only in Stackage Nighly, not in any LTS e.g. 22.30.
+  # we require tar 0.6+ due to https://github.com/snoyberg/keter/pull/292
+  - tar-0.6.2.0@sha256:619828cae098a7b6deeb0316e12f55011101d88f756787ed024ceedb81cf1eba,4576
+
+  # os-string is a dependency of tar 0.6.1.0 onwards. on Stackage starting from LTS 22.12.
+  - os-string-2.0.2.1@sha256:0bf4ff8f387d7fd05a43c18fa677dd02259c99d63c2d02c5823f152736513bef,3261
diff --git a/stack.yaml.lock b/stack.yaml.lock
new file mode 100644
index 0000000..50e78f5
--- /dev/null
+++ b/stack.yaml.lock
@@ -0,0 +1,26 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages:
+- completed:
+    hackage: tar-0.6.2.0@sha256:619828cae098a7b6deeb0316e12f55011101d88f756787ed024ceedb81cf1eba,4576
+    pantry-tree:
+      sha256: 1dde50961e9d1a6e6f820d918c0edbbd9673c83afdd300e0aae40a691e8151df
+      size: 2168
+  original:
+    hackage: tar-0.6.2.0@sha256:619828cae098a7b6deeb0316e12f55011101d88f756787ed024ceedb81cf1eba,4576
+- completed:
+    hackage: os-string-2.0.2.1@sha256:0bf4ff8f387d7fd05a43c18fa677dd02259c99d63c2d02c5823f152736513bef,3261
+    pantry-tree:
+      sha256: caa0b78b83a9d429324784e239c9bf33017f9f4a3c34ec8392b3d8a1e8968bd6
+      size: 2217
+  original:
+    hackage: os-string-2.0.2.1@sha256:0bf4ff8f387d7fd05a43c18fa677dd02259c99d63c2d02c5823f152736513bef,3261
+snapshots:
+- completed:
+    sha256: 5a59b2a405b3aba3c00188453be172b85893cab8ebc352b1ef58b0eae5d248a2
+    size: 650475
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/20/26.yaml
+  original: lts-20.26