diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -5,6 +5,12 @@
 ## Unreleased changes
 
 
+## Version 0.9.0.0
+
+-   Toolchain update
+-   Update to random version 1.3
+
+
 ## Version 0.8.0.0
 
 -   Adapt to breaking changes in upstream libraries (`data-default`).
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 # The ELynx Suite
 
-Version: 0.8.0.0.
+Version: 0.9.0.0.
 Reproducible evolution made easy.
 
 <p align="center"><img src="https://travis-ci.org/dschrempf/elynx.svg?branch=master"/></p>
@@ -73,9 +73,9 @@
     # OR: stack exec slynx -- --help
     # OR: slynx --help
 
-    ELynx Suite version 0.8.0.0.
+    ELynx Suite version 0.9.0.0.
     Developed by Dominik Schrempf.
-    Compiled on October 27, 2024, at 07:14 am, UTC.
+    Compiled on August 11, 2025, at 07:19 am, UTC.
     
     Usage: slynx [-v|--verbosity VALUE] [-o|--output-file-basename NAME]
                  [-f|--force] [--no-elynx-file] COMMAND
@@ -143,9 +143,9 @@
     # OR: stack exec slynx -- simulate --help
     # OR: slynx simulate --help
 
-    ELynx Suite version 0.8.0.0.
+    ELynx Suite version 0.9.0.0.
     Developed by Dominik Schrempf.
-    Compiled on October 27, 2024, at 07:14 am, UTC.
+    Compiled on August 11, 2025, at 07:19 am, UTC.
     
     Usage: slynx simulate (-t|--tree-file Name) [-s|--substitution-model MODEL]
                           [-m|--mixture-model MODEL] [-n|--global-normalization]
diff --git a/elynx-seq.cabal b/elynx-seq.cabal
--- a/elynx-seq.cabal
+++ b/elynx-seq.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               elynx-seq
-version:            0.8.0.0
+version:            0.9.0.0
 synopsis:           Handle molecular sequences
 description:
   Examine, modify, and simulate molecular sequences in a reproducible way. Please see the README on GitHub at <https://github.com/dschrempf/elynx>.
diff --git a/src/ELynx/Sequence/Alignment.hs b/src/ELynx/Sequence/Alignment.hs
--- a/src/ELynx/Sequence/Alignment.hs
+++ b/src/ELynx/Sequence/Alignment.hs
@@ -124,7 +124,7 @@
           "For each sequence, the "
             ++ show summaryLength
             ++ " first bases are shown."
-        | length a > summaryLength
+      | length a > summaryLength
       ]
     reportNumberSummary =
       [ BL.pack $
@@ -132,7 +132,7 @@
             ++ " out of "
             ++ show (nSequences a)
             ++ " sequences are shown."
-        | nSequences a > summaryNSequences
+      | nSequences a > summaryNSequences
       ]
 
 -- | Similar to 'S.summarizeSequenceList' but with different Header.
diff --git a/src/ELynx/Sequence/Divergence.hs b/src/ELynx/Sequence/Divergence.hs
--- a/src/ELynx/Sequence/Divergence.hs
+++ b/src/ELynx/Sequence/Divergence.hs
@@ -51,9 +51,9 @@
               i <- mi
               j <- mj
               Just $ modify m (i, j) (+ 1)
-            | (x, y) <- zip (VU.toList cs1) (VU.toList cs2),
-              let mi = S.lookupIndex x a,
-              let mj = S.lookupIndex y a
+          | (x, y) <- zip (VU.toList cs1) (VU.toList cs2),
+            let mi = S.lookupIndex x a,
+            let mj = S.lookupIndex y a
           ]
       return m
   where