diff --git a/CHANGELOG.md b/CHANGELOG.md
index 49f323607..adfb3e4d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,10 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+## [12.0.1](https://github.com/serialport/node-serialport/compare/v12.0.0...v12.0.1) (2023-09-26)
+
+**Note:** Version bump only for package serialport-monorepo
+
 # [12.0.0](https://github.com/serialport/node-serialport/compare/v11.0.1...v12.0.0) (2023-08-29)
 
 ### Bug Fixes
diff --git a/lerna.json b/lerna.json
index 9ceee70ca..e8ec2eed3 100644
--- a/lerna.json
+++ b/lerna.json
@@ -5,6 +5,6 @@
       "conventionalCommits": true
     }
   },
-  "version": "12.0.0",
+  "version": "12.0.1",
   "$schema": "node_modules/lerna/schemas/lerna-schema.json"
 }
diff --git a/package-lock.json b/package-lock.json
index b92147cdd..9ad0e8249 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -12427,7 +12427,7 @@
     },
     "packages/parser-packet-length": {
       "name": "@serialport/parser-packet-length",
-      "version": "12.0.0",
+      "version": "12.0.1",
       "license": "MIT",
       "devDependencies": {
         "typescript": "5.2.2"
@@ -12511,11 +12511,11 @@
     },
     "packages/repl": {
       "name": "@serialport/repl",
-      "version": "12.0.0",
+      "version": "12.0.1",
       "license": "MIT",
       "dependencies": {
         "promirepl": "^2.0.1",
-        "serialport": "12.0.0"
+        "serialport": "12.0.1"
       },
       "bin": {
         "serialport-repl": "dist/index.js"
@@ -12531,7 +12531,7 @@
       }
     },
     "packages/serialport": {
-      "version": "12.0.0",
+      "version": "12.0.1",
       "license": "MIT",
       "dependencies": {
         "@serialport/binding-mock": "10.2.2",
@@ -12540,7 +12540,7 @@
         "@serialport/parser-cctalk": "12.0.0",
         "@serialport/parser-delimiter": "12.0.0",
         "@serialport/parser-inter-byte-timeout": "12.0.0",
-        "@serialport/parser-packet-length": "12.0.0",
+        "@serialport/parser-packet-length": "12.0.1",
         "@serialport/parser-readline": "12.0.0",
         "@serialport/parser-ready": "12.0.0",
         "@serialport/parser-regex": "12.0.0",
diff --git a/packages/parser-packet-length/CHANGELOG.md b/packages/parser-packet-length/CHANGELOG.md
index 426fad48c..50d18e0a9 100644
--- a/packages/parser-packet-length/CHANGELOG.md
+++ b/packages/parser-packet-length/CHANGELOG.md
@@ -3,6 +3,10 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+## [12.0.1](https://github.com/serialport/node-serialport/compare/v12.0.0...v12.0.1) (2023-09-26)
+
+**Note:** Version bump only for package @serialport/parser-packet-length
+
 # [12.0.0](https://github.com/serialport/node-serialport/compare/v11.0.1...v12.0.0) (2023-08-29)
 
 **Note:** Version bump only for package @serialport/parser-packet-length
diff --git a/packages/parser-packet-length/lib/index.test.ts b/packages/parser-packet-length/lib/index.test.ts
index 8e3b17c9c..0846cb723 100644
--- a/packages/parser-packet-length/lib/index.test.ts
+++ b/packages/parser-packet-length/lib/index.test.ts
@@ -90,4 +90,45 @@ describe('DelimiterParser', () => {
     assert.deepEqual(spy.getCall(1).args[0], Buffer.concat([Buffer.from([0xaa, 0x02, 0x13, 0x00]), Buffer.from('Each and Every One\n')]))
     assert(spy.calledTwice)
   })
+
+  it('works with multiple delimiters', () => {
+    const spy = sinon.spy()
+    const parser = new PacketLengthParser({ delimiter: [0xaa, 0xbb], lengthOffset: 2, packetOverhead: 4, lengthBytes: 2 })
+    parser.on('data', spy)
+    parser.write(Buffer.from('\xbb\x01\x0d'))
+    parser.write(Buffer.from('\x00I love hobits\xaa\x02\x13\x00Each '))
+    parser.write(Buffer.from('and Every One\n'))
+
+    assert.deepEqual(spy.getCall(0).args[0], Buffer.concat([Buffer.from([0xbb, 0x01, 0x0d, 0x00]), Buffer.from('I love hobits')]))
+    assert.deepEqual(spy.getCall(1).args[0], Buffer.concat([Buffer.from([0xaa, 0x02, 0x13, 0x00]), Buffer.from('Each and Every One\n')]))
+    assert(spy.calledTwice)
+  })
+
+  it('works with multibyte delimiters', () => {
+    const spy = sinon.spy()
+    const parser = new PacketLengthParser({ delimiter: [0xababba], delimiterBytes: 3, lengthOffset: 3, packetOverhead: 4, lengthBytes: 1 })
+    parser.on('data', spy)
+    parser.write(Buffer.from([0xab, 0xab, 0xba, 0x0d]))
+    parser.write(Buffer.from('I love hobits'))
+    parser.write(Buffer.from([0xab, 0xab, 0xba, 0x13]))
+    parser.write(Buffer.from('Each and Every One\n'))
+
+    assert.deepEqual(spy.getCall(0).args[0], Buffer.concat([Buffer.from([0xab, 0xab, 0xba, 0x0d]), Buffer.from('I love hobits')]))
+    assert.deepEqual(spy.getCall(1).args[0], Buffer.concat([Buffer.from([0xab, 0xab, 0xba, 0x13]), Buffer.from('Each and Every One\n')]))
+    assert(spy.calledTwice)
+  })
+
+  it('works with multiple multibyte delimiters', () => {
+    const spy = sinon.spy()
+    const parser = new PacketLengthParser({ delimiter: [0xababba, 0xbaddad], delimiterBytes: 3, lengthOffset: 3, packetOverhead: 4, lengthBytes: 1 })
+    parser.on('data', spy)
+    parser.write(Buffer.from([0xab, 0xab, 0xba, 0x0d]))
+    parser.write(Buffer.from('I love hobits'))
+    parser.write(Buffer.from([0xba, 0xdd, 0xad, 0x13]))
+    parser.write(Buffer.from('Each and Every One\n'))
+
+    assert.deepEqual(spy.getCall(0).args[0], Buffer.concat([Buffer.from([0xab, 0xab, 0xba, 0x0d]), Buffer.from('I love hobits')]))
+    assert.deepEqual(spy.getCall(1).args[0], Buffer.concat([Buffer.from([0xba, 0xdd, 0xad, 0x13]), Buffer.from('Each and Every One\n')]))
+    assert(spy.calledTwice)
+  })
 })
diff --git a/packages/parser-packet-length/lib/index.ts b/packages/parser-packet-length/lib/index.ts
index bb362bcf3..4b19edf0c 100644
--- a/packages/parser-packet-length/lib/index.ts
+++ b/packages/parser-packet-length/lib/index.ts
@@ -1,8 +1,10 @@
 import { Transform, TransformCallback, TransformOptions } from 'stream'
 
 export interface PacketLengthOptions extends TransformOptions {
-  /** delimiter to use defaults to 0xaa */
-  delimiter?: number
+  /** delimiter(s) to use defaults to 0xaa */
+  delimiter?: number | number[]
+  /** delimiter length in bytes defaults to 1 */
+  delimiterBytes?: number
   /** overhead of packet (including length, delimiter and any checksum / packet footer) defaults to 2 */
   packetOverhead?: number
   /** number of bytes containing length defaults to 1 */
@@ -29,14 +31,15 @@ export interface PacketLengthOptions extends TransformOptions {
 export class PacketLengthParser extends Transform {
   buffer: Buffer
   start: boolean
-  opts: { delimiter: number; packetOverhead: number; lengthBytes: number; lengthOffset: number; maxLen: number }
+  opts: { delimiter: number[]; delimiterBytes: number; packetOverhead: number; lengthBytes: number; lengthOffset: number; maxLen: number }
   constructor(options: PacketLengthOptions = {}) {
     super(options)
 
-    const { delimiter = 0xaa, packetOverhead = 2, lengthBytes = 1, lengthOffset = 1, maxLen = 0xff } = options
+    const { delimiter = [0xaa], delimiterBytes = 1, packetOverhead = 2, lengthBytes = 1, lengthOffset = 1, maxLen = 0xff } = options
 
     this.opts = {
-      delimiter,
+      delimiter: ([] as number[]).concat(delimiter),
+      delimiterBytes,
       packetOverhead,
       lengthBytes,
       lengthOffset,
@@ -51,13 +54,8 @@ export class PacketLengthParser extends Transform {
     for (let ndx = 0; ndx < chunk.length; ndx++) {
       const byte = chunk[ndx]
 
-      if (byte === this.opts.delimiter) {
-        this.start = true
-      }
-
       if (true === this.start) {
         this.buffer = Buffer.concat([this.buffer, Buffer.from([byte])])
-
         if (this.buffer.length >= this.opts.lengthOffset + this.opts.lengthBytes) {
           const len = this.buffer.readUIntLE(this.opts.lengthOffset, this.opts.lengthBytes)
 
@@ -67,6 +65,17 @@ export class PacketLengthParser extends Transform {
             this.start = false
           }
         }
+      } else {
+        this.buffer = Buffer.concat([Buffer.from([byte]), this.buffer])
+        if (this.buffer.length === this.opts.delimiterBytes) {
+          const delimiter = this.buffer.readUIntLE(0, this.opts.delimiterBytes)
+          if (this.opts.delimiter.includes(delimiter)) {
+            this.start = true
+            this.buffer = Buffer.from([...this.buffer].reverse())
+          } else {
+            this.buffer = Buffer.from(this.buffer.subarray(1, this.buffer.length))
+          }
+        }
       }
     }
 
diff --git a/packages/parser-packet-length/package.json b/packages/parser-packet-length/package.json
index d68496d56..ce5324784 100644
--- a/packages/parser-packet-length/package.json
+++ b/packages/parser-packet-length/package.json
@@ -5,7 +5,7 @@
   "scripts": {
     "build": "tsc --build tsconfig-build.json"
   },
-  "version": "12.0.0",
+  "version": "12.0.1",
   "engines": {
     "node": ">=8.6.0"
   },
diff --git a/packages/repl/CHANGELOG.md b/packages/repl/CHANGELOG.md
index 7ac1bc9db..858c6a3a7 100644
--- a/packages/repl/CHANGELOG.md
+++ b/packages/repl/CHANGELOG.md
@@ -3,6 +3,10 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+## [12.0.1](https://github.com/serialport/node-serialport/compare/v12.0.0...v12.0.1) (2023-09-26)
+
+**Note:** Version bump only for package @serialport/repl
+
 # [12.0.0](https://github.com/serialport/node-serialport/compare/v11.0.1...v12.0.0) (2023-08-29)
 
 **Note:** Version bump only for package @serialport/repl
diff --git a/packages/repl/package.json b/packages/repl/package.json
index bf3346bfc..3cf5926d6 100644
--- a/packages/repl/package.json
+++ b/packages/repl/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@serialport/repl",
-  "version": "12.0.0",
+  "version": "12.0.1",
   "main": "./dist/index.js",
   "types": "./dist/index.d.ts",
   "scripts": {
@@ -11,7 +11,7 @@
   },
   "dependencies": {
     "promirepl": "^2.0.1",
-    "serialport": "12.0.0"
+    "serialport": "12.0.1"
   },
   "engines": {
     "node": ">=12.0.0"
diff --git a/packages/serialport/CHANGELOG.md b/packages/serialport/CHANGELOG.md
index dbf96a353..2fc794039 100644
--- a/packages/serialport/CHANGELOG.md
+++ b/packages/serialport/CHANGELOG.md
@@ -3,6 +3,10 @@
 All notable changes to this project will be documented in this file.
 See [Conventional Commits](https://conventionalcommits.org) for commit guidelines.
 
+## [12.0.1](https://github.com/serialport/node-serialport/compare/v12.0.0...v12.0.1) (2023-09-26)
+
+**Note:** Version bump only for package serialport
+
 # [12.0.0](https://github.com/serialport/node-serialport/compare/v11.0.1...v12.0.0) (2023-08-29)
 
 ### Bug Fixes
diff --git a/packages/serialport/package.json b/packages/serialport/package.json
index 757f78f74..483e3694b 100644
--- a/packages/serialport/package.json
+++ b/packages/serialport/package.json
@@ -1,6 +1,6 @@
 {
   "name": "serialport",
-  "version": "12.0.0",
+  "version": "12.0.1",
   "description": "Node.js package to access serial ports. Linux, OSX and Windows. Welcome your robotic JavaScript overlords. Better yet, program them!",
   "main": "./dist/index.js",
   "types": "./dist/index.d.ts",
@@ -56,7 +56,7 @@
     "@serialport/parser-cctalk": "12.0.0",
     "@serialport/parser-delimiter": "12.0.0",
     "@serialport/parser-inter-byte-timeout": "12.0.0",
-    "@serialport/parser-packet-length": "12.0.0",
+    "@serialport/parser-packet-length": "12.0.1",
     "@serialport/parser-readline": "12.0.0",
     "@serialport/parser-ready": "12.0.0",
     "@serialport/parser-regex": "12.0.0",