diff --git a/package-lock.json b/package-lock.json
index 462fcb18..3c9bb154 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -31,7 +31,7 @@
         "@types/mocha": "^10.0.6",
         "@types/node": "^18.19.11",
         "@types/sinon": "^17.0.3",
-        "chai": "^4.4.1",
+        "chai": "^5.0.3",
         "eslint": "^8.56.0",
         "eslint-config-teppeis": "^19.1.0",
         "mocha": "^10.2.0",
@@ -1206,12 +1206,12 @@
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-      "resolved": "https://registry.npmjs.org/assertion-error/-/assertion-error-1.1.0.tgz",
-      "integrity": "sha512-jgsaNduz+ndvGyFt3uSuWqvy4lCnIJiovtouQN5JZHOKCS2QuhEdbcQHFhVksz2N2U9hXJo8odG7ETyWlEeuDw==",
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/assertion-error/-/assertion-error-2.0.1.tgz",
+      "integrity": "sha512-Izi8RQcffqCeNVgFigKli1ssklIbpHnCYc6AknXGYoB6grJqyeby7jv12JUQgmTAnIDnbck1uxksT4dzN3PWBA==",
       "dev": true,
       "engines": {
-        "node": "*"
+        "node": ">=12"
       }
     },
     "node_modules/available-typed-arrays": {
@@ -1323,21 +1323,19 @@
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     "node_modules/chai": {
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-      "resolved": "https://registry.npmjs.org/chai/-/chai-4.4.1.tgz",
-      "integrity": "sha512-13sOfMv2+DWduEU+/xbun3LScLoqN17nBeTLUsmDfKdoiC1fr0n9PU4guu4AhRcOVFk/sW8LyZWHuhWtQZiF+g==",
+      "version": "5.0.3",
+      "resolved": "https://registry.npmjs.org/chai/-/chai-5.0.3.tgz",
+      "integrity": "sha512-wKGCtYv2kVY5WEjKqQ3fSIZWtTFveZCtzinhTZbx3/trVkxefiwovhpU9kRVCwxvKKCEjTWXPdM1/T7zPoDgow==",
       "dev": true,
       "dependencies": {
-        "assertion-error": "^1.1.0",
-        "check-error": "^1.0.3",
-        "deep-eql": "^4.1.3",
-        "get-func-name": "^2.0.2",
-        "loupe": "^2.3.6",
-        "pathval": "^1.1.1",
-        "type-detect": "^4.0.8"
+        "assertion-error": "^2.0.1",
+        "check-error": "^2.0.0",
+        "deep-eql": "^5.0.1",
+        "loupe": "^3.1.0",
+        "pathval": "^2.0.0"
       },
       "engines": {
-        "node": ">=4"
+        "node": ">=12"
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     "node_modules/chalk": {
@@ -1357,15 +1355,12 @@
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-      "resolved": "https://registry.npmjs.org/check-error/-/check-error-1.0.3.tgz",
-      "integrity": "sha512-iKEoDYaRmd1mxM90a2OEfWhjsjPpYPuQ+lMYsoxB126+t8fw7ySEO48nmDg5COTjxDI65/Y2OWpeEHk3ZOe8zg==",
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/check-error/-/check-error-2.0.0.tgz",
+      "integrity": "sha512-tjLAOBHKVxtPoHe/SA7kNOMvhCRdCJ3vETdeY0RuAc9popf+hyaSV6ZEg9hr4cpWF7jmo/JSWEnLDrnijS9Tog==",
       "dev": true,
-      "dependencies": {
-        "get-func-name": "^2.0.2"
-      },
       "engines": {
-        "node": "*"
+        "node": ">= 16"
       }
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     "node_modules/chokidar": {
@@ -1592,13 +1587,10 @@
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     "node_modules/deep-eql": {
-      "version": "4.1.3",
-      "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-4.1.3.tgz",
-      "integrity": "sha512-WaEtAOpRA1MQ0eohqZjpGD8zdI0Ovsm8mmFhaDN8dvDZzyoUMcYDnf5Y6iu7HTXxf8JDS23qWa4a+hKCDyOPzw==",
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-5.0.1.tgz",
+      "integrity": "sha512-nwQCf6ne2gez3o1MxWifqkciwt0zhl0LO1/UwVu4uMBuPmflWM4oQ70XMqHqnBJA+nhzncaqL9HVL6KkHJ28lw==",
       "dev": true,
-      "dependencies": {
-        "type-detect": "^4.0.0"
-      },
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         "node": ">=6"
       }
@@ -3409,9 +3401,9 @@
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     "node_modules/loupe": {
-      "version": "2.3.7",
-      "resolved": "https://registry.npmjs.org/loupe/-/loupe-2.3.7.tgz",
-      "integrity": "sha512-zSMINGVYkdpYSOBmLi0D1Uo7JU9nVdQKrHxC8eYlV+9YKK9WePqAlL7lSlorG/U2Fw1w0hTBmaa/jrQ3UbPHtA==",
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/loupe/-/loupe-3.1.0.tgz",
+      "integrity": "sha512-qKl+FrLXUhFuHUoDJG7f8P8gEMHq9NFS0c6ghXG1J0rldmZFQZoNVv/vyirE9qwCIhWZDsvEFd1sbFu3GvRQFg==",
       "dev": true,
       "dependencies": {
         "get-func-name": "^2.0.1"
@@ -4096,12 +4088,12 @@
       }
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     "node_modules/pathval": {
-      "version": "1.1.1",
-      "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.1.tgz",
-      "integrity": "sha512-Dp6zGqpTdETdR63lehJYPeIOqpiNBNtc7BpWSLrOje7UaIsE5aY92r/AunQA7rsXvet3lrJ3JnZX29UPTKXyKQ==",
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/pathval/-/pathval-2.0.0.tgz",
+      "integrity": "sha512-vE7JKRyES09KiunauX7nd2Q9/L7lhok4smP9RZTDeD4MVs72Dp2qNFVz39Nz5a0FVEW0BJR6C0DYrq6unoziZA==",
       "dev": true,
       "engines": {
-        "node": "*"
+        "node": ">= 14.16"
       }
     },
     "node_modules/picomatch": {
diff --git a/package.json b/package.json
index e7331e0c..8614b5f9 100644
--- a/package.json
+++ b/package.json
@@ -47,7 +47,7 @@
     "@types/mocha": "^10.0.6",
     "@types/node": "^18.19.11",
     "@types/sinon": "^17.0.3",
-    "chai": "^4.4.1",
+    "chai": "^5.0.3",
     "eslint": "^8.56.0",
     "eslint-config-teppeis": "^19.1.0",
     "mocha": "^10.2.0",