diff --git a/Gemfile.lock b/Gemfile.lock
index c2dbf60..c50b2a8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -10,18 +10,11 @@ GIT
       rainbow
       yard
 
-PATH
-  remote: ../..
-  specs:
-    ast-merge (1.1.0)
-      tree_haver (~> 3.1, >= 3.1.0)
-      version_gem (~> 1.1, >= 1.1.9)
-
 PATH
   remote: .
   specs:
     rbs-merge (1.0.0)
-      ast-merge (~> 1.0)
+      ast-merge (>= 1, < 3)
       rbs (>= 1.6)
       version_gem (~> 1.1, >= 1.1.9)
 
@@ -36,6 +29,9 @@ GEM
       rake (>= 10)
       thor (>= 0.14)
     ast (2.4.3)
+    ast-merge (2.0.0)
+      tree_haver (~> 3.1, >= 3.1.1)
+      version_gem (~> 1.1, >= 1.1.9)
     backports (3.25.3)
     benchmark (0.5.0)
     bigdecimal (3.3.1)
@@ -294,7 +290,7 @@ GEM
       delegate (~> 0.1)
       rspec (~> 3.0)
       timecop (>= 0.7, < 1)
-    tree_haver (3.1.0)
+    tree_haver (3.1.1)
       version_gem (~> 1.1, >= 1.1.9)
     tsort (0.2.0)
     ttfunk (1.8.0)
@@ -327,7 +323,6 @@ PLATFORMS
 DEPENDENCIES
   addressable (>= 2.8, < 3)
   appraisal2 (~> 3.0)
-  ast-merge!
   benchmark (~> 0.4, >= 0.4.1)
   bundler-audit (~> 0.9.2)
   debug (>= 1.1)
@@ -368,7 +363,7 @@ CHECKSUMS
   ansi (1.5.0) sha256=5408253274e33d9d27d4a98c46d2998266fd51cba58a7eb9d08f50e57ed23592
   appraisal2 (3.0.0) sha256=f1b4e742cf8ebef5e9fbb76c416a8c16edfe0727964a5a17b44adfc37b701aed
   ast (2.4.3) sha256=954615157c1d6a382bc27d690d973195e79db7f55e9765ac7c481c60bdb4d383
-  ast-merge (1.1.0)
+  ast-merge (2.0.0) sha256=bcd68642464fe85908866434e3e436a4bff3ad83ea6fff065f77531aa4612ea4
   backports (3.25.3) sha256=94298d32dc3c40ca15633b54e282780b49e2db0c045f602ea1907e4f63a17235
   benchmark (0.5.0) sha256=465df122341aedcb81a2a24b4d3bd19b6c67c1530713fd533f3ff034e419236c
   bigdecimal (3.3.1) sha256=eaa01e228be54c4f9f53bf3cc34fe3d5e845c31963e7fcc5bedb05a4e7d52218
@@ -468,7 +463,7 @@ CHECKSUMS
   thor (1.4.0) sha256=8763e822ccb0f1d7bee88cde131b19a65606657b847cc7b7b4b82e772bcd8a3d
   timecop (0.9.10) sha256=12ba45ce57cdcf6b1043cb6cdffa6381fd89ce10d369c28a7f6f04dc1b0cd8eb
   timecop-rspec (1.0.3) sha256=005f14841bb606dcaefb060e321b5388e2e59537742bee8b3a9a9a40e598fab9
-  tree_haver (3.1.0) sha256=ff5f78ac463427442294b469c4b9f621272f0e66af888afc524f0deb33910d81
+  tree_haver (3.1.1) sha256=74c437fb795f1d8271f112ac7b413ec452346555c6f7140a34148eadfc5a5045
   tsort (0.2.0) sha256=9650a793f6859a43b6641671278f79cfead60ac714148aabe4e3f0060480089f
   ttfunk (1.8.0) sha256=a7cbc7e489cc46e979dde04d34b5b9e4f5c8f1ee5fc6b1a7be39b829919d20ca
   unicode-display_width (3.2.0) sha256=0cdd96b5681a5949cdbc2c55e7b420facae74c4aaf9a9815eee1087cb1853c42
diff --git a/rbs-merge.gemspec b/rbs-merge.gemspec
index 02aabef..f51e488 100644
--- a/rbs-merge.gemspec
+++ b/rbs-merge.gemspec
@@ -85,7 +85,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency("rbs", ">= 1.6")                                  # ruby >= 2.6.0
 
   # Shared merge infrastructure
-  spec.add_dependency("ast-merge", "~> 1.0")                            # ruby >= 3.2.0
+  spec.add_dependency("ast-merge", ">= 1", "< 3")                         # ruby >= 3.2.0
 
   # Utilities
   spec.add_dependency("version_gem", "~> 1.1", ">= 1.1.9")              # ruby >= 2.2.0