diff --git a/.gitignore b/.gitignore
index ccc2e3c..755450a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,4 +25,7 @@ yarn-error.log*
 
 *.d.ts
 *.js
-*.js.map
\ No newline at end of file
+*.js.map
+
+# VSCode
+.vscode
\ No newline at end of file
diff --git a/config.ts b/config.ts
index 312deed..1581753 100644
--- a/config.ts
+++ b/config.ts
@@ -9,5 +9,9 @@ export const TRANSFORM_OPTIONS = [
     value: 'pluralized-methods',
     version: '5.0.0',
   },
-  //{ description: 'Transform the deprecated signatures in Express v4', value: 'signature-deprecated', version: '5.0.0' },
+  { 
+    description: 'Transform the deprecated signatures in Express v4', 
+    value: 'v4-deprecated-signatures', 
+    version: '5.0.0'
+  },
 ]
diff --git a/transforms/__test__/v4-deprecated-signatures.spec.ts b/transforms/__test__/v4-deprecated-signatures.spec.ts
new file mode 100644
index 0000000..4df36b4
--- /dev/null
+++ b/transforms/__test__/v4-deprecated-signatures.spec.ts
@@ -0,0 +1,3 @@
+import { testSpecBuilder } from './util'
+
+testSpecBuilder('v4-deprecated-signatures')
diff --git a/transforms/__testfixtures__/v4-deprecated-signatures/json.input.ts b/transforms/__testfixtures__/v4-deprecated-signatures/json.input.ts
new file mode 100644
index 0000000..56fc2b4
--- /dev/null
+++ b/transforms/__testfixtures__/v4-deprecated-signatures/json.input.ts
@@ -0,0 +1,57 @@
+import express from "express";
+
+const app = express();
+
+app.get("/json", function (req, res) {    
+    res.json({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/json", function (req, response) {
+    response.json({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/json", (req, res) => {
+    res.json({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/json", (req, response) => {
+    response.json({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/json", function (req, res) {
+    res.json({}, 200);
+});
+
+app.get("/json", function (req, response) {
+    response.json({}, 200);
+});
+
+app.get("/json", (req, res) => {
+    res.json({}, 200);
+});
+
+app.get("/json", (req, response) => {
+    response.json({}, 200);
+});
+
+// Still valid syntax -- START
+app.get("/json", function (req, res) {
+    res.json(null)
+    res.json({ user: 'tobi' })
+})
+
+app.get("/json", function (req, response) {
+    response.json(null)
+    response.json({ user: 'tobi' })
+})
+
+app.get("/json", function (req, res) {
+    res.json(null)
+    res.json({ user: 'tobi' })
+})
+
+app.get("/json", function (req, response) {
+    response.json(null)
+    response.json({ user: 'tobi' })
+})
+// Still valid syntax -- END
\ No newline at end of file
diff --git a/transforms/__testfixtures__/v4-deprecated-signatures/json.output.ts b/transforms/__testfixtures__/v4-deprecated-signatures/json.output.ts
new file mode 100644
index 0000000..92905a1
--- /dev/null
+++ b/transforms/__testfixtures__/v4-deprecated-signatures/json.output.ts
@@ -0,0 +1,57 @@
+import express from "express";
+
+const app = express();
+
+app.get("/json", function (req, res) {    
+    res.status(200).json({ user: "Username", isValid: true });
+});
+
+app.get("/json", function (req, response) {
+    response.status(200).json({ user: "Username", isValid: true });
+});
+
+app.get("/json", (req, res) => {
+    res.status(200).json({ user: "Username", isValid: true });
+});
+
+app.get("/json", (req, response) => {
+    response.status(200).json({ user: "Username", isValid: true });
+});
+
+app.get("/json", function (req, res) {
+    res.status(200).json({});
+});
+
+app.get("/json", function (req, response) {
+    response.status(200).json({});
+});
+
+app.get("/json", (req, res) => {
+    res.status(200).json({});
+});
+
+app.get("/json", (req, response) => {
+    response.status(200).json({});
+});
+
+// Still valid syntax -- START
+app.get("/json", function (req, res) {
+    res.json(null)
+    res.json({ user: 'tobi' })
+})
+
+app.get("/json", function (req, response) {
+    response.json(null)
+    response.json({ user: 'tobi' })
+})
+
+app.get("/json", function (req, res) {
+    res.json(null)
+    res.json({ user: 'tobi' })
+})
+
+app.get("/json", function (req, response) {
+    response.json(null)
+    response.json({ user: 'tobi' })
+})
+// Still valid syntax -- END
\ No newline at end of file
diff --git a/transforms/__testfixtures__/v4-deprecated-signatures/jsonp.input.ts b/transforms/__testfixtures__/v4-deprecated-signatures/jsonp.input.ts
new file mode 100644
index 0000000..99b2b2f
--- /dev/null
+++ b/transforms/__testfixtures__/v4-deprecated-signatures/jsonp.input.ts
@@ -0,0 +1,57 @@
+import express from "express";
+
+const app = express();
+
+app.get("/jsonp", function (req, res) {
+    res.jsonp({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/jsonp", function (req, response) {
+    response.jsonp({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/jsonp", (req, res) => {
+    res.jsonp({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/jsonp", (req, response) => {
+    response.jsonp({ user: "Username", isValid: true }, 200);
+});
+
+app.get("/jsonp", function (req, res) {
+    res.jsonp({}, 200);
+});
+
+app.get("/jsonp", function (req, response) {
+    response.jsonp({}, 200);
+});
+
+app.get("/jsonp", (req, res) => {
+    res.jsonp({}, 200)
+});
+
+app.get("/jsonp", (req, response) => {
+    response.jsonp({}, 200)
+});
+
+// Still valid syntax -- START
+app.get("/jsonp", function (req, res) {
+    res.jsonp(null)
+    res.jsonp({ user: 'tobi' })
+})
+
+app.get("/jsonp", function (req, response) {
+    response.jsonp(null)
+    response.jsonp({ user: 'tobi' })
+})
+
+app.get("/jsonp", function (req, res) {
+    res.jsonp(null)
+    res.jsonp({ user: 'tobi' })
+})
+
+app.get("/jsonp", function (req, response) {
+    response.jsonp(null)
+    response.jsonp({ user: 'tobi' })
+})
+// Still valid syntax -- END
\ No newline at end of file
diff --git a/transforms/__testfixtures__/v4-deprecated-signatures/jsonp.output.ts b/transforms/__testfixtures__/v4-deprecated-signatures/jsonp.output.ts
new file mode 100644
index 0000000..2a8e4c1
--- /dev/null
+++ b/transforms/__testfixtures__/v4-deprecated-signatures/jsonp.output.ts
@@ -0,0 +1,57 @@
+import express from "express";
+
+const app = express();
+
+app.get("/jsonp", function (req, res) {
+    res.status(200).jsonp({ user: "Username", isValid: true });
+});
+
+app.get("/jsonp", function (req, response) {
+    response.status(200).jsonp({ user: "Username", isValid: true });
+});
+
+app.get("/jsonp", (req, res) => {
+    res.status(200).jsonp({ user: "Username", isValid: true });
+});
+
+app.get("/jsonp", (req, response) => {
+    response.status(200).jsonp({ user: "Username", isValid: true });
+});
+
+app.get("/jsonp", function (req, res) {
+    res.status(200).jsonp({});
+});
+
+app.get("/jsonp", function (req, response) {
+    response.status(200).jsonp({});
+});
+
+app.get("/jsonp", (req, res) => {
+    res.status(200).jsonp({})
+});
+
+app.get("/jsonp", (req, response) => {
+    response.status(200).jsonp({})
+});
+
+// Still valid syntax -- START
+app.get("/jsonp", function (req, res) {
+    res.jsonp(null)
+    res.jsonp({ user: 'tobi' })
+})
+
+app.get("/jsonp", function (req, response) {
+    response.jsonp(null)
+    response.jsonp({ user: 'tobi' })
+})
+
+app.get("/jsonp", function (req, res) {
+    res.jsonp(null)
+    res.jsonp({ user: 'tobi' })
+})
+
+app.get("/jsonp", function (req, response) {
+    response.jsonp(null)
+    response.jsonp({ user: 'tobi' })
+})
+// Still valid syntax -- END
\ No newline at end of file
diff --git a/transforms/__testfixtures__/v4-deprecated-signatures/send.input.ts b/transforms/__testfixtures__/v4-deprecated-signatures/send.input.ts
new file mode 100644
index 0000000..d2d38fa
--- /dev/null
+++ b/transforms/__testfixtures__/v4-deprecated-signatures/send.input.ts
@@ -0,0 +1,61 @@
+import express from "express";
+
+const app = express();
+
+app.get("/send", function (req, res) {
+    res.send(200, { hello: "world" });
+});
+
+app.get("/send", function (req, response) {
+    response.send(200, "Hello World");
+});
+
+app.get("/send", function (req, res) {
+    res.send(200);
+});
+
+app.get("/send", function (req, res) {
+    res.send(200, true);
+});
+
+app.get("/send", (req, res) => {
+    res.send(200, { hello: "world" });
+});
+
+app.get("/send", (req, res) => {
+    res.send(200);
+});
+
+app.get("/send", (req, response) => {
+    response.send(200);
+});
+
+app.get("/send", (req, response) => {
+    response.send(200, true);
+});
+
+// Still valid syntax -- START
+app.get("/send", function (req, res) {
+    res.send(Buffer.from('whoop'));
+    res.send({ some: 'json' });
+    res.send('<p>some html</p>');
+});
+
+app.get("/send", function (req, response) {
+    response.send(Buffer.from('whoop'));
+    response.send({ some: 'json' });
+    response.send('<p>some html</p>');
+});
+
+app.get("/send", (req, response) => {
+    response.send(Buffer.from('whoop'));
+    response.send({ some: 'json' });
+    response.send('<p>some html</p>');
+});
+
+app.get("/send", (req, res) => {
+    res.send(Buffer.from('whoop'));
+    res.send({ some: 'json' });
+    res.send('<p>some html</p>');
+});
+// Still valid syntax -- END
\ No newline at end of file
diff --git a/transforms/__testfixtures__/v4-deprecated-signatures/send.output.ts b/transforms/__testfixtures__/v4-deprecated-signatures/send.output.ts
new file mode 100644
index 0000000..f317983
--- /dev/null
+++ b/transforms/__testfixtures__/v4-deprecated-signatures/send.output.ts
@@ -0,0 +1,61 @@
+import express from "express";
+
+const app = express();
+
+app.get("/send", function (req, res) {
+    res.status(200).send({ hello: "world" });
+});
+
+app.get("/send", function (req, response) {
+    response.status(200).send("Hello World");
+});
+
+app.get("/send", function (req, res) {
+    res.sendStatus(200);
+});
+
+app.get("/send", function (req, res) {
+    res.status(200).send(true);
+});
+
+app.get("/send", (req, res) => {
+    res.status(200).send({ hello: "world" });
+});
+
+app.get("/send", (req, res) => {
+    res.sendStatus(200);
+});
+
+app.get("/send", (req, response) => {
+    response.sendStatus(200);
+});
+
+app.get("/send", (req, response) => {
+    response.status(200).send(true);
+});
+
+// Still valid syntax -- START
+app.get("/send", function (req, res) {
+    res.send(Buffer.from('whoop'));
+    res.send({ some: 'json' });
+    res.send('<p>some html</p>');
+});
+
+app.get("/send", function (req, response) {
+    response.send(Buffer.from('whoop'));
+    response.send({ some: 'json' });
+    response.send('<p>some html</p>');
+});
+
+app.get("/send", (req, response) => {
+    response.send(Buffer.from('whoop'));
+    response.send({ some: 'json' });
+    response.send('<p>some html</p>');
+});
+
+app.get("/send", (req, res) => {
+    res.send(Buffer.from('whoop'));
+    res.send({ some: 'json' });
+    res.send('<p>some html</p>');
+});
+// Still valid syntax -- END
\ No newline at end of file
diff --git a/transforms/magic-redirect.ts b/transforms/magic-redirect.ts
index 9eefd66..eb988c3 100644
--- a/transforms/magic-redirect.ts
+++ b/transforms/magic-redirect.ts
@@ -1,11 +1,8 @@
 import {
   type API,
-  type ASTNode,
   type ASTPath,
-  type ArrowFunctionExpression,
   CallExpression,
   type FileInfo,
-  type FunctionExpression,
   callExpression,
   identifier,
   literal,
@@ -13,8 +10,7 @@ import {
   memberExpression,
 } from 'jscodeshift'
 import { getParsedFile } from '../utils/parse'
-
-const parentExpressionType = ['ArrowFunctionExpression', 'FunctionExpression'] as const
+import { recursiveParent } from '../utils/recursiveParent'
 
 const unifiedMagicString = (path: ASTPath<CallExpression>, projectRequestName: string) => {
   const pathArguments = path.value.arguments
@@ -31,22 +27,6 @@ const unifiedMagicString = (path: ASTPath<CallExpression>, projectRequestName: s
   }
 }
 
-const recursiveParent = (parent: ASTPath<ASTNode>): string | null => {
-  if (parentExpressionType.some((type) => parent.value.type === type)) {
-    const foundNode = parent.value as unknown as ArrowFunctionExpression | FunctionExpression
-    if (foundNode.params[0].type === 'Identifier') {
-      return foundNode.params[0].name
-    }
-    return null
-  }
-
-  if (parent?.parentPath) {
-    return recursiveParent(parent.parentPath)
-  }
-
-  return null
-}
-
 export default function transformer(file: FileInfo, _api: API) {
   const parsedFile = getParsedFile(file)
 
diff --git a/transforms/param.ts b/transforms/param.ts
new file mode 100644
index 0000000..e5b9b1c
--- /dev/null
+++ b/transforms/param.ts
@@ -0,0 +1,20 @@
+import type { API, FileInfo } from 'jscodeshift'
+import { CallExpression, withParser } from 'jscodeshift'
+
+export default function transformer(file: FileInfo, _api: API): string {
+  const parser = withParser('ts')
+
+  return (
+    parser(file.source)
+      .find(CallExpression, {
+        callee: {
+          property: {
+            name: 'json',
+          },
+        },
+      })
+      // TODO: app.param(fn): This method has been deprecated. Instead, access parameters directly via req.params, or use req.body or req.query as needed.
+      // Add comment line before with this information
+      .toSource()
+  )
+}
diff --git a/transforms/v4-deprecated-signatures.ts b/transforms/v4-deprecated-signatures.ts
new file mode 100644
index 0000000..56d96ed
--- /dev/null
+++ b/transforms/v4-deprecated-signatures.ts
@@ -0,0 +1,97 @@
+import type { API, ASTPath, FileInfo } from 'jscodeshift'
+import { CallExpression, callExpression, identifier, memberExpression, withParser } from 'jscodeshift'
+import { recursiveParent } from '../utils/recursiveParent'
+
+const separateStatusAndBody = (path: ASTPath<CallExpression>, calleePropertyName: string) => {
+  const pathArguments = path.node.arguments
+  const statusParamIndex = pathArguments.findIndex((arg) => arg.type === 'NumericLiteral')
+  const bodyParamIndex = pathArguments.findIndex((arg) => arg.type !== 'NumericLiteral')
+
+  path.replace(
+    callExpression(
+      memberExpression(
+        callExpression(
+          memberExpression(identifier(recursiveParent(path.parentPath, 1) || 'res'), identifier('status')),
+          [pathArguments[statusParamIndex]],
+        ),
+        identifier(calleePropertyName),
+      ),
+      [pathArguments[bodyParamIndex]],
+    ),
+  )
+}
+
+export default function transformer(file: FileInfo, _api: API): string {
+  const parser = withParser('ts')
+  const parsedFile = parser(file.source)
+
+  parsedFile
+    .find(CallExpression, {
+      callee: {
+        property: {
+          name: 'send',
+        },
+      },
+    })
+    .map((path) => {
+      // from v3: https://expressjs.com/en/3x/api.html#res.send
+      const pathArguments = path.node.arguments
+
+      if (pathArguments.length === 2) {
+        separateStatusAndBody(path, 'send')
+      } else if (pathArguments.length === 1) {
+        const statusValue = pathArguments[0].type === 'NumericLiteral' ? pathArguments[0].value : false
+
+        if (statusValue) {
+          path.replace(
+            callExpression(
+              memberExpression(identifier(recursiveParent(path.parentPath, 1) || 'res'), identifier('sendStatus')),
+              [pathArguments[0]],
+            ),
+          )
+        }
+      }
+
+      return path
+    })
+
+  parsedFile
+    .find(CallExpression, {
+      callee: {
+        property: {
+          name: 'json',
+        },
+      },
+    })
+    .map((path) => {
+      // from v3: https://expressjs.com/en/3x/api.html#res.json
+      const pathArguments = path.node.arguments
+
+      if (pathArguments.length === 2) {
+        separateStatusAndBody(path, 'json')
+      }
+
+      return path
+    })
+
+  parsedFile
+    .find(CallExpression, {
+      callee: {
+        property: {
+          name: 'jsonp',
+        },
+      },
+    })
+    .map((path) => {
+      // from v3: https://expressjs.com/en/3x/api.html#res.jsonp
+      const pathArguments = path.node.arguments
+
+      if (pathArguments.length === 2) {
+        separateStatusAndBody(path, 'jsonp')
+      }
+
+      return path
+    })
+
+  return parsedFile.toSource()
+}
diff --git a/utils/recursiveParent.ts b/utils/recursiveParent.ts
new file mode 100644
index 0000000..ba904eb
--- /dev/null
+++ b/utils/recursiveParent.ts
@@ -0,0 +1,23 @@
+import type { ASTNode, ASTPath, ArrowFunctionExpression, FunctionExpression } from 'jscodeshift'
+
+const defaultParentExpressionType = ['ArrowFunctionExpression', 'FunctionExpression'] as const
+
+export const recursiveParent = (
+  parent: ASTPath<ASTNode>,
+  paramIndex = 0,
+  parentExpressionType = defaultParentExpressionType,
+): string | null => {
+  if (parentExpressionType.some((type) => parent.value.type === type)) {
+    const foundNode = parent.value as unknown as ArrowFunctionExpression | FunctionExpression
+    if (foundNode.params[paramIndex].type === 'Identifier') {
+      return foundNode.params[paramIndex].name
+    }
+    return null
+  }
+
+  if (parent?.parentPath) {
+    return recursiveParent(parent.parentPath, paramIndex, parentExpressionType)
+  }
+
+  return null
+}