diff --git a/cabal.project.release b/cabal.project.release
index f0118629..65bc1fe2 100644
--- a/cabal.project.release
+++ b/cabal.project.release
@@ -1,7 +1,7 @@
 import: cabal.project
 executable-static: True
 executable-stripping: True
-index-state: hackage.haskell.org 2026-06-15T00:00:00Z
+index-state: hackage.haskell.org 2026-08-20T00:00:00Z
 
 package *
   ghc-options:
diff --git a/jbeam-edit.cabal b/jbeam-edit.cabal
index f3e0b62c..6a0b857d 100644
--- a/jbeam-edit.cabal
+++ b/jbeam-edit.cabal
@@ -49,6 +49,10 @@ flag dump-ast
     default:     False
     manual:      True
 
+flag modern-containers
+    description: Require containers 0.8
+    manual:      True
+
 flag transformation
     description: Enable transformation (experimental)
     default:     False
@@ -107,7 +111,7 @@ library
         text >=2.1.2,
         vector >=0.13
 
-    if (!flag(transformation) && !flag(dump-ast))
+    if flag(modern-containers)
         build-depends: containers >=0.8
 
     if os(windows)
@@ -154,7 +158,7 @@ library jbeam-edit-transformation
         text >=2.1.2,
         vector >=0.13
 
-    if (!flag(transformation) && !flag(dump-ast))
+    if flag(modern-containers)
         build-depends: containers >=0.8
 
     if os(windows)
@@ -202,7 +206,7 @@ executable jbeam-edit
         text >=2.1.2,
         vector >=0.13
 
-    if (!flag(transformation) && !flag(dump-ast))
+    if flag(modern-containers)
         build-depends: containers >=0.8
 
     if os(windows)
@@ -240,7 +244,7 @@ executable jbeam-edit-dump-ast
         text >=2.1.2,
         vector >=0.13
 
-    if (!flag(transformation) && !flag(dump-ast))
+    if flag(modern-containers)
         build-depends: containers >=0.8
 
     if os(windows)
@@ -296,7 +300,7 @@ test-suite jbeam-edit-test
         text >=2.1.2,
         vector >=0.13
 
-    if (!flag(transformation) && !flag(dump-ast))
+    if flag(modern-containers)
         build-depends: containers >=0.8
 
     if os(windows)
@@ -341,7 +345,7 @@ test-suite jbeam-edit-transformation-test
         text >=2.1.2,
         vector >=0.13
 
-    if (!flag(transformation) && !flag(dump-ast))
+    if flag(modern-containers)
         build-depends: containers >=0.8
 
     if os(windows)
@@ -385,7 +389,7 @@ benchmark jbeam-edit-bench
         text >=2.1.2,
         vector >=0.13
 
-    if (!flag(transformation) && !flag(dump-ast))
+    if flag(modern-containers)
         build-depends: containers >=0.8
 
     if os(windows)
diff --git a/package.yaml b/package.yaml
index 04f0a267..0114c952 100644
--- a/package.yaml
+++ b/package.yaml
@@ -56,7 +56,7 @@ ghc-options:
   - -Wredundant-constraints
 
 when:
-  - condition: '! flag(transformation) && ! flag(dump-ast)'
+  - condition: flag(modern-containers)
     dependencies: [containers >= 0.8]
   - condition: os(windows)
     ghc-options: -optc-Os -optl-static
@@ -74,6 +74,10 @@ flags:
     description: Use executable-relative example paths (for Windows release builds)
     default: false
     manual: true
+  modern-containers:
+    description: Require containers 0.8
+    manual: true
+    default: true
 
 internal-libraries:
   jbeam-edit-transformation:
diff --git a/src/JbeamEdit/Formatting/Rules.hs b/src/JbeamEdit/Formatting/Rules.hs
index 59f68477..cede8c5e 100644
--- a/src/JbeamEdit/Formatting/Rules.hs
+++ b/src/JbeamEdit/Formatting/Rules.hs
@@ -283,7 +283,7 @@ sameBy matchMode f = go
        in res && go ps bs
     go ps bs = Seq.null ps && (Seq.null bs || PrefixMatch == matchMode)
 
--- TODO: when possible upgrade to containers 0.8 and migrate to M.filterKeys
+-- TODO: migrate to M.filterKeys once the stack snapshot ships containers 0.8
 findPropertiesForCursor :: MatchMode -> NC.NodeCursor -> RuleSet -> Rule
 findPropertiesForCursor matchMode cursor (RuleSet rs) =
   fold (M.filterWithKey (const . compareCursorAndPattern matchMode cursor) rs)
diff --git a/stack.yaml b/stack.yaml
index 28c1ca11..6a63b046 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -6,6 +6,7 @@ flags:
     transformation: false
     dump-ast: false
     windows-example-paths: false
+    modern-containers: false
 
 ghc-options:
   jbeam-edit: "-Werror -Wwarn=unused-imports"