diff --git a/lib/v4-periphery b/lib/v4-periphery
index 151b2829..3819809f 160000
--- a/lib/v4-periphery
+++ b/lib/v4-periphery
@@ -1 +1 @@
-Subproject commit 151b28293733b9cd8a310babc15408fe1ba55c35
+Subproject commit 3819809f8c3aa6224ece98e83abe5fbfd15a0788
diff --git a/test/integration-tests/V3ToV4Migration.test.ts b/test/integration-tests/V3ToV4Migration.test.ts
index 62941214..79e08e7e 100644
--- a/test/integration-tests/V3ToV4Migration.test.ts
+++ b/test/integration-tests/V3ToV4Migration.test.ts
@@ -969,7 +969,7 @@ describe('V3 to V4 Migration Tests:', () => {
   describe('V4 Commands', () => {
     beforeEach(async () => {
       // initialize new pool on v4
-      await v4PositionManager.connect(bob).initializePool(USDC_WETH.poolKey, USDC_WETH.price, '0x')
+      await v4PositionManager.connect(bob).initializePool(USDC_WETH.poolKey, USDC_WETH.price)
     })
 
     it('mint v4 succeeds', async () => {
@@ -1658,11 +1658,10 @@ describe('V3 to V4 Migration Tests:', () => {
           tickSpacing: 10,
           hooks: '0x0000000000000000000000000000000000000000',
         },
-        '79228162514264337593543950336',
-        '0x'
+        '79228162514264337593543950336'
       )
 
-      await v4PositionManager.connect(bob).initializePool(ETH_USDC.poolKey, ETH_USDC.price, '0x')
+      await v4PositionManager.connect(bob).initializePool(ETH_USDC.poolKey, ETH_USDC.price)
     })
     it('migrate with minting succeeds', async () => {
       // Bob max-approves the v3PM to access his USDC and WETH
diff --git a/test/integration-tests/gas-tests/V3ToV4Migration.gas.test.ts b/test/integration-tests/gas-tests/V3ToV4Migration.gas.test.ts
index 6d83e8a7..7c4ddbd7 100644
--- a/test/integration-tests/gas-tests/V3ToV4Migration.gas.test.ts
+++ b/test/integration-tests/gas-tests/V3ToV4Migration.gas.test.ts
@@ -260,8 +260,8 @@ describe('V3 to V4 Migration Gas Tests', () => {
   describe('V4 Commands', () => {
     beforeEach(async () => {
       // initialize new pool on v4
-      await v4PositionManager.connect(bob).initializePool(USDC_WETH.poolKey, USDC_WETH.price, '0x')
-      await v4PositionManager.connect(bob).initializePool(ETH_USDC.poolKey, ETH_USDC.price, '0x')
+      await v4PositionManager.connect(bob).initializePool(USDC_WETH.poolKey, USDC_WETH.price)
+      await v4PositionManager.connect(bob).initializePool(ETH_USDC.poolKey, ETH_USDC.price)
     })
 
     describe('mint', () => {
diff --git a/test/integration-tests/gas-tests/__snapshots__/V3ToV4Migration.gas.test.ts.snap b/test/integration-tests/gas-tests/__snapshots__/V3ToV4Migration.gas.test.ts.snap
index 00d7c729..d2090132 100644
--- a/test/integration-tests/gas-tests/__snapshots__/V3ToV4Migration.gas.test.ts.snap
+++ b/test/integration-tests/gas-tests/__snapshots__/V3ToV4Migration.gas.test.ts.snap
@@ -31,34 +31,34 @@ Object {
 exports[`V3 to V4 Migration Gas Tests V4 Commands increase gas: increase 1`] = `
 Object {
   "calldataByteLength": 2084,
-  "gasUsed": 228044,
+  "gasUsed": 228073,
 }
 `;
 
 exports[`V3 to V4 Migration Gas Tests V4 Commands increase gas: migrate and increase 1`] = `
 Object {
   "calldataByteLength": 2980,
-  "gasUsed": 452893,
+  "gasUsed": 452916,
 }
 `;
 
 exports[`V3 to V4 Migration Gas Tests V4 Commands mint gas: migrate and mint 1`] = `
 Object {
   "calldataByteLength": 2500,
-  "gasUsed": 591127,
+  "gasUsed": 591168,
 }
 `;
 
 exports[`V3 to V4 Migration Gas Tests V4 Commands mint gas: migrate weth position into eth position with forwarding 1`] = `
 Object {
   "calldataByteLength": 2788,
-  "gasUsed": 595274,
+  "gasUsed": 595307,
 }
 `;
 
 exports[`V3 to V4 Migration Gas Tests V4 Commands mint gas: mint 1`] = `
 Object {
   "calldataByteLength": 1604,
-  "gasUsed": 437555,
+  "gasUsed": 437596,
 }
 `;
diff --git a/test/integration-tests/shared/constants.ts b/test/integration-tests/shared/constants.ts
index 7a35eb2f..294fafd2 100644
--- a/test/integration-tests/shared/constants.ts
+++ b/test/integration-tests/shared/constants.ts
@@ -25,3 +25,4 @@ export const V3_FACTORY_MAINNET = '0x1F98431c8aD98523631AE4a59f267346ea31F984'
 export const V3_INIT_CODE_HASH_MAINNET = '0xe34f199b19b2b4f47f68442619d555527d244f78a3297ea89325f843f87b8b54'
 export const V2_INIT_CODE_HASH_MAINNET = '0x96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f'
 export const V3_NFT_POSITION_MANAGER_MAINNET = '0xC36442b4a4522E871399CD717aBDD847Ab11FE88'
+export const V4_POSITION_DESCRIPTOR_ADDRESS = '0x0000000000000000000000000000000000000000' // TODO, deploy this in-line and use the proper address in posm's constructor
diff --git a/test/integration-tests/shared/deployUniversalRouter.ts b/test/integration-tests/shared/deployUniversalRouter.ts
index 5f067e79..e127edec 100644
--- a/test/integration-tests/shared/deployUniversalRouter.ts
+++ b/test/integration-tests/shared/deployUniversalRouter.ts
@@ -8,6 +8,7 @@ import {
   V3_INIT_CODE_HASH_MAINNET,
   PERMIT2_ADDRESS,
   V3_NFT_POSITION_MANAGER_MAINNET,
+  V4_POSITION_DESCRIPTOR_ADDRESS,
 } from './constants'
 import { deployV4PoolManager, deployV4PositionManager } from './v4Helpers'
 
@@ -22,7 +23,8 @@ export async function deployRouter(v4PoolManager?: string, mockReentrantWETH?: s
     poolInitCodeHash: V3_INIT_CODE_HASH_MAINNET,
     v4PoolManager: poolManager,
     v3NFTPositionManager: V3_NFT_POSITION_MANAGER_MAINNET,
-    v4PositionManager: (await deployV4PositionManager(poolManager, PERMIT2_ADDRESS)).address,
+    v4PositionManager: (await deployV4PositionManager(poolManager, PERMIT2_ADDRESS, V4_POSITION_DESCRIPTOR_ADDRESS))
+      .address,
   }
 
   const routerFactory = await ethers.getContractFactory('UniversalRouter')
diff --git a/test/integration-tests/shared/v4Helpers.ts b/test/integration-tests/shared/v4Helpers.ts
index 6c8e790b..5b25c6a5 100644
--- a/test/integration-tests/shared/v4Helpers.ts
+++ b/test/integration-tests/shared/v4Helpers.ts
@@ -58,12 +58,17 @@ export const ETH_USDC = {
   tickUpper: ETH_USDC_TICK_UPPER,
 }
 
-export async function deployV4PositionManager(v4PoolManager: string, permit2: string): Promise<PositionManager> {
+export async function deployV4PositionManager(
+  v4PoolManager: string,
+  permit2: string,
+  v4PositionDescriptor: string
+): Promise<PositionManager> {
   const positionManagerFactory = await ethers.getContractFactory('PositionManager')
   const positionManager = (await positionManagerFactory.deploy(
     v4PoolManager,
     permit2,
-    50000
+    50000,
+    v4PositionDescriptor
   )) as unknown as PositionManager
   return positionManager
 }
@@ -75,7 +80,7 @@ export async function deployV4PoolManager(): Promise<PoolManager> {
 }
 
 export async function initializeV4Pool(poolManager: PoolManager, poolKey: any, sqrtPrice: BigNumber) {
-  await poolManager.initialize(poolKey, sqrtPrice.toString(), '0x')
+  await poolManager.initialize(poolKey, sqrtPrice.toString())
 }
 
 export async function addLiquidityToV4Pool(