diff --git a/package.json b/package.json
index a9772dd1..481bde31 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@across-protocol/sdk",
   "author": "UMA Team",
-  "version": "3.4.12",
+  "version": "3.4.13",
   "license": "AGPL-3.0",
   "homepage": "https://docs.across.to/reference/sdk",
   "files": [
diff --git a/src/clients/BundleDataClient/utils/SuperstructUtils.ts b/src/clients/BundleDataClient/utils/SuperstructUtils.ts
index dd3462fe..c7a0ce01 100644
--- a/src/clients/BundleDataClient/utils/SuperstructUtils.ts
+++ b/src/clients/BundleDataClient/utils/SuperstructUtils.ts
@@ -10,6 +10,7 @@ import {
   pattern,
   boolean,
   defaulted,
+  union,
   type,
 } from "superstruct";
 import { BigNumber } from "../../../utils";
@@ -17,7 +18,7 @@ import { BigNumber } from "../../../utils";
 const PositiveIntegerStringSS = pattern(string(), /\d+/);
 const Web3AddressSS = pattern(string(), /^0x[a-fA-F0-9]{40}$/);
 
-const BigNumberType = coerce(instance(BigNumber), string(), (value) => {
+const BigNumberType = coerce(instance(BigNumber), union([string(), number()]), (value) => {
   try {
     // Attempt to convert the string to a BigNumber
     return BigNumber.from(value);
@@ -41,7 +42,7 @@ const V3RelayDataSS = {
   originChainId: number(),
   depositor: string(),
   recipient: string(),
-  depositId: number(),
+  depositId: BigNumberType,
   message: string(),
 };
 
@@ -91,6 +92,7 @@ const V3FillSS = {
   repaymentChainId: number(),
   relayExecutionInfo: V3RelayExecutionEventInfoSS,
   quoteTimestamp: number(),
+  messageHash: optional(string()),
 };
 
 const V3FillWithBlockSS = {
diff --git a/src/clients/SpokePoolClient.ts b/src/clients/SpokePoolClient.ts
index ef1b3173..18a077c2 100644
--- a/src/clients/SpokePoolClient.ts
+++ b/src/clients/SpokePoolClient.ts
@@ -12,6 +12,8 @@ import {
   getRelayDataHash,
   isDefined,
   toBN,
+  bnOne,
+  isUnsafeDepositId,
 } from "../utils";
 import {
   paginatedEventQuery,
@@ -46,8 +48,8 @@ type SpokePoolUpdateSuccess = {
   success: true;
   currentTime: number;
   oldestTime: number;
-  firstDepositId: number;
-  latestDepositId: number;
+  firstDepositId: BigNumber;
+  latestDepositId: BigNumber;
   events: Log[][];
   searchEndBlock: number;
 };
@@ -66,7 +68,7 @@ export class SpokePoolClient extends BaseAbstractClient {
   protected oldestTime = 0;
   protected depositHashes: { [depositHash: string]: DepositWithBlock } = {};
   protected depositHashesToFills: { [depositHash: string]: FillWithBlock[] } = {};
-  protected speedUps: { [depositorAddress: string]: { [depositId: number]: SpeedUpWithBlock[] } } = {};
+  protected speedUps: { [depositorAddress: string]: { [depositId: string]: SpeedUpWithBlock[] } } = {};
   protected slowFillRequests: { [relayDataHash: string]: SlowFillRequestWithBlock } = {};
   protected depositRoutes: { [originToken: string]: { [DestinationChainId: number]: boolean } } = {};
   protected tokensBridged: TokensBridged[] = [];
@@ -74,10 +76,10 @@ export class SpokePoolClient extends BaseAbstractClient {
   protected relayerRefundExecutions: RelayerRefundExecutionWithBlock[] = [];
   protected queryableEventNames: string[] = [];
   protected configStoreClient: AcrossConfigStoreClient | undefined;
-  public earliestDepositIdQueried = Number.MAX_SAFE_INTEGER;
-  public latestDepositIdQueried = 0;
-  public firstDepositIdForSpokePool = Number.MAX_SAFE_INTEGER;
-  public lastDepositIdForSpokePool = Number.MAX_SAFE_INTEGER;
+  public earliestDepositIdQueried = MAX_BIG_INT;
+  public latestDepositIdQueried = bnZero;
+  public firstDepositIdForSpokePool = MAX_BIG_INT;
+  public lastDepositIdForSpokePool = MAX_BIG_INT;
   public fills: { [OriginChainId: number]: FillWithBlock[] } = {};
 
   /**
@@ -232,7 +234,7 @@ export class SpokePoolClient extends BaseAbstractClient {
    */
   public appendMaxSpeedUpSignatureToDeposit(deposit: DepositWithBlock): DepositWithBlock {
     const { depositId, depositor } = deposit;
-    const speedups = this.speedUps[depositor]?.[depositId];
+    const speedups = this.speedUps[depositor]?.[depositId.toString()];
     if (!isDefined(speedups) || speedups.length === 0) {
       return deposit;
     }
@@ -265,7 +267,7 @@ export class SpokePoolClient extends BaseAbstractClient {
    * @param depositId The unique ID of the deposit being queried.
    * @returns The corresponding deposit if found, undefined otherwise.
    */
-  public getDeposit(depositId: number): DepositWithBlock | undefined {
+  public getDeposit(depositId: BigNumber): DepositWithBlock | undefined {
     const depositHash = this.getDepositHash({ depositId, originChainId: this.chainId });
     return this.depositHashes[depositHash];
   }
@@ -295,7 +297,7 @@ export class SpokePoolClient extends BaseAbstractClient {
    * Retrieves speed up requests grouped by depositor and depositId.
    * @returns A mapping of depositor addresses to deposit ids with their corresponding speed up requests.
    */
-  public getSpeedUps(): { [depositorAddress: string]: { [depositId: number]: SpeedUpWithBlock[] } } {
+  public getSpeedUps(): { [depositorAddress: string]: { [depositId: string]: SpeedUpWithBlock[] } } {
     return this.speedUps;
   }
 
@@ -365,7 +367,7 @@ export class SpokePoolClient extends BaseAbstractClient {
     );
 
     // Log any invalid deposits with same deposit id but different params.
-    const invalidFillsForDeposit = invalidFills.filter((x) => x.depositId === deposit.depositId);
+    const invalidFillsForDeposit = invalidFills.filter((x) => x.depositId.eq(deposit.depositId));
     if (invalidFillsForDeposit.length > 0) {
       this.logger.warn({
         at: "SpokePoolClient",
@@ -396,7 +398,7 @@ export class SpokePoolClient extends BaseAbstractClient {
    * @note This hash is used to match deposits and fills together.
    * @note This hash takes the form of: `${depositId}-${originChainId}`.
    */
-  public getDepositHash(event: { depositId: number; originChainId: number }): string {
+  public getDepositHash(event: { depositId: BigNumber; originChainId: number }): string {
     return `${event.depositId}-${event.originChainId}`;
   }
 
@@ -405,7 +407,7 @@ export class SpokePoolClient extends BaseAbstractClient {
    * @param blockTag The block number to search for the deposit ID at.
    * @returns The deposit ID.
    */
-  public _getDepositIdAtBlock(blockTag: number): Promise<number> {
+  public _getDepositIdAtBlock(blockTag: number): Promise<BigNumber> {
     return getDepositIdAtBlock(this.spokePool as SpokePool, blockTag);
   }
 
@@ -438,10 +440,11 @@ export class SpokePoolClient extends BaseAbstractClient {
    */
   protected async _update(eventsToQuery: string[]): Promise<SpokePoolUpdate> {
     // Find the earliest known depositId. This assumes no deposits were placed in the deployment block.
-    let firstDepositId: number = this.firstDepositIdForSpokePool;
-    if (firstDepositId === Number.MAX_SAFE_INTEGER) {
+    let firstDepositId = this.firstDepositIdForSpokePool;
+    if (firstDepositId.eq(MAX_BIG_INT)) {
       firstDepositId = await this.spokePool.numberOfDeposits({ blockTag: this.deploymentBlock });
-      if (isNaN(firstDepositId) || firstDepositId < 0) {
+      firstDepositId = BigNumber.from(firstDepositId); // Cast input to a big number.
+      if (!BigNumber.isBigNumber(firstDepositId) || firstDepositId.lt(bnZero)) {
         throw new Error(`SpokePoolClient::update: Invalid first deposit id (${firstDepositId})`);
       }
     }
@@ -491,9 +494,10 @@ export class SpokePoolClient extends BaseAbstractClient {
     ]);
     this.log("debug", `Time to query new events from RPC for ${this.chainId}: ${Date.now() - timerStart} ms`);
 
-    const [currentTime, numberOfDeposits] = multicallFunctions.map(
+    const [currentTime, _numberOfDeposits] = multicallFunctions.map(
       (fn, idx) => spokePool.interface.decodeFunctionResult(fn, multicallOutput[idx])[0]
     );
+    const _latestDepositId = BigNumber.from(_numberOfDeposits).sub(bnOne);
 
     if (!BigNumber.isBigNumber(currentTime) || currentTime.lt(this.currentTime)) {
       const errMsg = BigNumber.isBigNumber(currentTime)
@@ -510,7 +514,7 @@ export class SpokePoolClient extends BaseAbstractClient {
       currentTime: currentTime.toNumber(), // uint32
       oldestTime: oldestTime.toNumber(),
       firstDepositId,
-      latestDepositId: Math.max(numberOfDeposits - 1, 0),
+      latestDepositId: _latestDepositId.gt(bnZero) ? _latestDepositId : bnZero,
       searchEndBlock: searchConfig.toBlock,
       events,
     };
@@ -579,10 +583,10 @@ export class SpokePoolClient extends BaseAbstractClient {
         }
         assign(this.depositHashes, [this.getDepositHash(deposit)], deposit);
 
-        if (deposit.depositId < this.earliestDepositIdQueried) {
+        if (deposit.depositId.lt(this.earliestDepositIdQueried) && !isUnsafeDepositId(deposit.depositId)) {
           this.earliestDepositIdQueried = deposit.depositId;
         }
-        if (deposit.depositId > this.latestDepositIdQueried) {
+        if (deposit.depositId.gt(this.latestDepositIdQueried) && !isUnsafeDepositId(deposit.depositId)) {
           this.latestDepositIdQueried = deposit.depositId;
         }
       }
@@ -594,7 +598,7 @@ export class SpokePoolClient extends BaseAbstractClient {
 
       for (const event of speedUpEvents) {
         const speedUp = { ...spreadEventWithBlockNumber(event), originChainId: this.chainId } as SpeedUpWithBlock;
-        assign(this.speedUps, [speedUp.depositor, speedUp.depositId], [speedUp]);
+        assign(this.speedUps, [speedUp.depositor, speedUp.depositId.toString()], [speedUp]);
 
         // Find deposit hash matching this speed up event and update the deposit data associated with the hash,
         // if the hash+data exists.
@@ -778,7 +782,7 @@ export class SpokePoolClient extends BaseAbstractClient {
     return this.oldestTime;
   }
 
-  async findDeposit(depositId: number, destinationChainId: number): Promise<DepositWithBlock> {
+  async findDeposit(depositId: BigNumber, destinationChainId: number): Promise<DepositWithBlock> {
     // Binary search for event search bounds. This way we can get the blocks before and after the deposit with
     // deposit ID = fill.depositId and use those blocks to optimize the search for that deposit.
     // Stop searches after a maximum # of searches to limit number of eth_call requests. Make an
@@ -807,7 +811,7 @@ export class SpokePoolClient extends BaseAbstractClient {
     );
     const tStop = Date.now();
 
-    const event = query.find(({ args }) => args["depositId"] === depositId);
+    const event = query.find(({ args }) => args["depositId"].eq(depositId));
     if (event === undefined) {
       const srcChain = getNetworkName(this.chainId);
       const dstChain = getNetworkName(destinationChainId);
diff --git a/src/clients/mocks/MockSpokePoolClient.ts b/src/clients/mocks/MockSpokePoolClient.ts
index 7e9f2ed9..3d3a4aa7 100644
--- a/src/clients/mocks/MockSpokePoolClient.ts
+++ b/src/clients/mocks/MockSpokePoolClient.ts
@@ -14,7 +14,7 @@ import {
   SlowFillLeaf,
   SpeedUp,
 } from "../../interfaces";
-import { toBN, toBNWei, getCurrentTime, randomAddress } from "../../utils";
+import { toBN, toBNWei, getCurrentTime, randomAddress, BigNumber, bnZero, bnOne, bnMax } from "../../utils";
 import { SpokePoolClient, SpokePoolUpdate } from "../SpokePoolClient";
 import { HubPoolClient } from "../HubPoolClient";
 import { EventManager, EventOverrides, getEventManager } from "./MockEvents";
@@ -26,8 +26,8 @@ export class MockSpokePoolClient extends SpokePoolClient {
   public eventManager: EventManager;
   private destinationTokenForChainOverride: Record<number, string> = {};
   // Allow tester to set the numberOfDeposits() returned by SpokePool at a block height.
-  public depositIdAtBlock: number[] = [];
-  public numberOfDeposits = 0;
+  public depositIdAtBlock: BigNumber[] = [];
+  public numberOfDeposits = bnZero;
 
   constructor(
     logger: winston.Logger,
@@ -57,21 +57,21 @@ export class MockSpokePoolClient extends SpokePoolClient {
     this.latestBlockSearched = blockNumber;
   }
 
-  setDepositIds(_depositIds: number[]): void {
+  setDepositIds(_depositIds: BigNumber[]): void {
     this.depositIdAtBlock = [];
     if (_depositIds.length === 0) {
       return;
     }
     let lastDepositId = _depositIds[0];
     for (let i = 0; i < _depositIds.length; i++) {
-      if (_depositIds[i] < lastDepositId) {
+      if (_depositIds[i].lt(lastDepositId)) {
         throw new Error("deposit ID must be equal to or greater than previous");
       }
       this.depositIdAtBlock[i] = _depositIds[i];
       lastDepositId = _depositIds[i];
     }
   }
-  _getDepositIdAtBlock(blockTag: number): Promise<number> {
+  _getDepositIdAtBlock(blockTag: number): Promise<BigNumber> {
     return Promise.resolve(this.depositIdAtBlock[blockTag]);
   }
 
@@ -96,13 +96,13 @@ export class MockSpokePoolClient extends SpokePoolClient {
     // Update latestDepositIdQueried.
     const idx = eventsToQuery.indexOf("V3FundsDeposited");
     const latestDepositId = (events[idx] ?? []).reduce(
-      (depositId, event) => Math.max(depositId, (event.args["depositId"] ?? 0) as number),
+      (depositId, event) => bnMax(depositId, event.args["depositId"] ?? bnZero),
       this.latestDepositIdQueried
     );
 
     return Promise.resolve({
       success: true,
-      firstDepositId: 0,
+      firstDepositId: bnZero,
       latestDepositId,
       currentTime,
       oldestTime: 0,
@@ -122,8 +122,8 @@ export class MockSpokePoolClient extends SpokePoolClient {
     const { blockNumber, transactionIndex } = deposit;
     let { depositId, depositor, destinationChainId, inputToken, inputAmount, outputToken, outputAmount } = deposit;
     depositId ??= this.numberOfDeposits;
-    assert(depositId >= this.numberOfDeposits, `${depositId} < ${this.numberOfDeposits}`);
-    this.numberOfDeposits = depositId + 1;
+    assert(depositId.gte(this.numberOfDeposits), `${depositId} < ${this.numberOfDeposits}`);
+    this.numberOfDeposits = depositId.add(bnOne);
 
     destinationChainId ??= random(1, 42161, false);
     depositor ??= randomAddress();
@@ -168,7 +168,7 @@ export class MockSpokePoolClient extends SpokePoolClient {
     const { blockNumber, transactionIndex } = fill;
     let { originChainId, depositId, inputToken, inputAmount, outputAmount, fillDeadline, relayer } = fill;
     originChainId ??= random(1, 42161, false);
-    depositId ??= random(1, 100_000, false);
+    depositId ??= BigNumber.from(random(1, 100_000, false));
     inputToken ??= randomAddress();
     inputAmount ??= toBNWei(random(1, 1000, false));
     outputAmount ??= inputAmount;
diff --git a/src/constants.ts b/src/constants.ts
index 82579196..a424d3fd 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -10,7 +10,7 @@ export {
   TOKEN_SYMBOLS_MAP,
 } from "@across-protocol/constants";
 
-export const { AddressZero: ZERO_ADDRESS } = ethersConstants;
+export const { AddressZero: ZERO_ADDRESS, HashZero: ZERO_BYTES } = ethersConstants;
 
 // 2^96 - 1 is a conservative erc20 max allowance.
 export const MAX_SAFE_ALLOWANCE = "79228162514264337593543950335";
@@ -33,7 +33,7 @@ export const TRANSFER_THRESHOLD_MAX_CONFIG_STORE_VERSION = 1;
 export const ARWEAVE_TAG_APP_NAME = "across-protocol";
 
 // A hardcoded version number used, by default, to tag all Arweave records.
-export const ARWEAVE_TAG_APP_VERSION = 2;
+export const ARWEAVE_TAG_APP_VERSION = 3;
 
 /**
  * A default list of chain Ids that the protocol supports. This is outlined
diff --git a/src/interfaces/SpokePool.ts b/src/interfaces/SpokePool.ts
index 9bccb894..83ea6297 100644
--- a/src/interfaces/SpokePool.ts
+++ b/src/interfaces/SpokePool.ts
@@ -10,7 +10,7 @@ export interface RelayData {
   originChainId: number;
   depositor: string;
   recipient: string;
-  depositId: number;
+  depositId: BigNumber;
   inputToken: string;
   inputAmount: BigNumber;
   outputToken: string;
@@ -67,7 +67,7 @@ export interface FillWithBlock extends Fill, SortableEvent {}
 export interface SpeedUp {
   depositor: string;
   depositorSignature: string;
-  depositId: number;
+  depositId: BigNumber;
   originChainId: number;
   updatedRecipient: string;
   updatedOutputAmount: BigNumber;
diff --git a/src/utils/BigNumberUtils.ts b/src/utils/BigNumberUtils.ts
index 27476328..a4c42a29 100644
--- a/src/utils/BigNumberUtils.ts
+++ b/src/utils/BigNumberUtils.ts
@@ -62,3 +62,14 @@ export const toBN = (num: BigNumberish, rounding: "floor" | "round" | "ceil" = "
   // Otherwise, it is a string int and we can parse it directly.
   return BigNumber.from(num.toString());
 };
+
+/**
+ * Compares two BigNumbers and returns the maximum. Order does not matter.
+ *
+ * @param val The first BigNumber to compare.
+ * @param cmp The second BigNumber to compare.
+ * @returns The greater of the two BigNumbers.
+ */
+export const bnMax = (val: BigNumber, cmp: BigNumber) => {
+  return val.gt(cmp) ? val : cmp;
+};
diff --git a/src/utils/DepositUtils.ts b/src/utils/DepositUtils.ts
index 5dd97aec..06d61e81 100644
--- a/src/utils/DepositUtils.ts
+++ b/src/utils/DepositUtils.ts
@@ -52,7 +52,7 @@ export async function queryHistoricalDepositForFill(
 
   const { depositId } = fill;
   let { firstDepositIdForSpokePool: lowId, lastDepositIdForSpokePool: highId } = spokePoolClient;
-  if (depositId < lowId || depositId > highId) {
+  if (depositId.lt(lowId) || depositId.gt(highId)) {
     return {
       found: false,
       code: InvalidFill.DepositIdInvalid,
@@ -61,7 +61,7 @@ export async function queryHistoricalDepositForFill(
   }
 
   ({ earliestDepositIdQueried: lowId, latestDepositIdQueried: highId } = spokePoolClient);
-  if (depositId >= lowId && depositId <= highId) {
+  if (depositId.gte(lowId) && depositId.lte(highId)) {
     const originChain = getNetworkName(fill.originChainId);
     const deposit = spokePoolClient.getDeposit(depositId);
     if (isDefined(deposit)) {
diff --git a/src/utils/EventUtils.ts b/src/utils/EventUtils.ts
index 7a321c69..f305e80e 100644
--- a/src/utils/EventUtils.ts
+++ b/src/utils/EventUtils.ts
@@ -3,6 +3,7 @@ import { Result } from "@ethersproject/abi";
 import { Contract, Event, EventFilter } from "ethers";
 import { Log, SortableEvent } from "../interfaces";
 import { delay } from "./common";
+import { isDefined, toBN, BigNumberish } from "./";
 
 const maxRetries = 3;
 const retrySleepTime = 10;
@@ -58,6 +59,13 @@ export function spreadEvent(args: Result | Record<string, unknown>): { [key: str
   if (returnedObject.rootBundleId) {
     returnedObject.rootBundleId = Number(returnedObject.rootBundleId);
   }
+  // If depositId is included in the event, cast it to a BigNumber. Need to check if it is defined since the deposit ID can
+  // be 0, which would still make this evaluate as false.
+  if (isDefined(returnedObject.depositId)) {
+    // Assuming a numeric output, we can safely cast the unknown to BigNumberish since the depositId will either be a uint32 (and therefore a TypeScript `number`),
+    // or a uint256 (and therefore an ethers BigNumber).
+    returnedObject.depositId = toBN(returnedObject.depositId as BigNumberish);
+  }
 
   return returnedObject;
 }
diff --git a/src/utils/SpokeUtils.ts b/src/utils/SpokeUtils.ts
index 23962bd0..dee660cb 100644
--- a/src/utils/SpokeUtils.ts
+++ b/src/utils/SpokeUtils.ts
@@ -1,10 +1,10 @@
 import assert from "assert";
 import { BytesLike, Contract, PopulatedTransaction, providers, utils as ethersUtils } from "ethers";
-import { CHAIN_IDs, MAX_SAFE_DEPOSIT_ID, ZERO_ADDRESS } from "../constants";
+import { CHAIN_IDs, MAX_SAFE_DEPOSIT_ID, ZERO_ADDRESS, ZERO_BYTES } from "../constants";
 import { Deposit, Fill, FillStatus, RelayData, SlowFillRequest } from "../interfaces";
 import { SpokePoolClient } from "../clients";
 import { chunk } from "./ArrayUtils";
-import { BigNumber, toBN } from "./BigNumberUtils";
+import { BigNumber, toBN, bnOne, bnZero } from "./BigNumberUtils";
 import { isDefined } from "./TypeGuards";
 import { getNetworkName } from "./NetworkUtils";
 
@@ -70,7 +70,7 @@ export function populateV3Relay(
  *        // where the deposit with deposit ID = targetDepositId was created.
  */
 export async function getBlockRangeForDepositId(
-  targetDepositId: number,
+  targetDepositId: BigNumber,
   initLow: number,
   initHigh: number,
   maxSearches: number,
@@ -79,6 +79,12 @@ export async function getBlockRangeForDepositId(
   low: number;
   high: number;
 }> {
+  // We can only perform this search when we have a safe deposit ID.
+  if (isUnsafeDepositId(targetDepositId))
+    throw new Error(
+      `Target deposit ID ${targetDepositId} is deterministic and therefore unresolvable via a binary search.`
+    );
+
   // Resolve the deployment block number.
   const deploymentBlock = spokePool.deploymentBlock;
 
@@ -109,13 +115,13 @@ export async function getBlockRangeForDepositId(
   });
 
   // Define a mapping of block numbers to number of deposits at that block. This saves repeated lookups.
-  const queriedIds: Record<number, number> = {};
+  const queriedIds: Record<number, BigNumber> = {};
 
   // Define a llambda function to get the deposit ID at a block number. This function will first check the
   // queriedIds cache to see if the deposit ID at the block number has already been queried. If not, it will
   // make an eth_call request to get the deposit ID at the block number. It will then cache the deposit ID
   // in the queriedIds cache.
-  const _getDepositIdAtBlock = async (blockNumber: number): Promise<number> => {
+  const _getDepositIdAtBlock = async (blockNumber: number): Promise<BigNumber> => {
     queriedIds[blockNumber] ??= await spokePool._getDepositIdAtBlock(blockNumber);
     return queriedIds[blockNumber];
   };
@@ -128,7 +134,7 @@ export async function getBlockRangeForDepositId(
 
   // If the deposit ID at the initial high block is less than the target deposit ID, then we know that
   // the target deposit ID must be greater than the initial high block, so we can throw an error.
-  if (highestDepositIdInRange <= targetDepositId) {
+  if (highestDepositIdInRange.lte(targetDepositId)) {
     // initLow   = 5: Deposits Num: 10
     //                                     // targetId = 11  <- fail (triggers this error)          // 10 <= 11
     //                                     // targetId = 10  <- fail (triggers this error)          // 10 <= 10
@@ -140,7 +146,7 @@ export async function getBlockRangeForDepositId(
 
   // If the deposit ID at the initial low block is greater than the target deposit ID, then we know that
   // the target deposit ID must be less than the initial low block, so we can throw an error.
-  if (lowestDepositIdInRange > targetDepositId) {
+  if (lowestDepositIdInRange.gt(targetDepositId)) {
     // initLow   = 5: Deposits Num: 10
     // initLow-1 = 4: Deposits Num:  2
     //                                     // targetId = 1 <- fail (triggers this error)
@@ -154,7 +160,6 @@ export async function getBlockRangeForDepositId(
   // Define the low and high block numbers for the binary search.
   let low = initLow;
   let high = initHigh;
-
   // Define the number of searches performed so far.
   let searches = 0;
 
@@ -166,12 +171,12 @@ export async function getBlockRangeForDepositId(
     const midDepositId = await _getDepositIdAtBlock(mid);
 
     // Let's define the latest ID of the current midpoint block.
-    const accountedIdByMidBlock = midDepositId - 1;
+    const accountedIdByMidBlock = midDepositId.sub(bnOne);
 
     // If our target deposit ID is less than the smallest range of our
     // midpoint deposit ID range, then we know that the target deposit ID
     // must be in the lower half of the block range.
-    if (targetDepositId <= accountedIdByMidBlock) {
+    if (targetDepositId.lte(accountedIdByMidBlock)) {
       high = mid;
     }
     // If our target deposit ID is greater than the largest range of our
@@ -200,10 +205,11 @@ export async function getBlockRangeForDepositId(
  * @param blockTag The block number to search for the deposit ID at.
  * @returns The deposit ID.
  */
-export async function getDepositIdAtBlock(contract: Contract, blockTag: number): Promise<number> {
-  const depositIdAtBlock = await contract.numberOfDeposits({ blockTag });
+export async function getDepositIdAtBlock(contract: Contract, blockTag: number): Promise<BigNumber> {
+  const _depositIdAtBlock = await contract.numberOfDeposits({ blockTag });
+  const depositIdAtBlock = toBN(_depositIdAtBlock);
   // Sanity check to ensure that the deposit ID is an integer and is greater than or equal to zero.
-  if (!Number.isInteger(depositIdAtBlock) || depositIdAtBlock < 0) {
+  if (depositIdAtBlock.lt(bnZero)) {
     throw new Error("Invalid deposit count");
   }
   return depositIdAtBlock;
@@ -244,7 +250,7 @@ export function getRelayHashFromEvent(e: Deposit | Fill | SlowFillRequest): stri
   return getRelayDataHash(e, e.destinationChainId);
 }
 
-export function isUnsafeDepositId(depositId: number): boolean {
+export function isUnsafeDepositId(depositId: BigNumber): boolean {
   // SpokePool.unsafeDepositV3() produces a uint256 depositId by hashing the msg.sender, depositor and input
   // uint256 depositNonce. There is a possibility that this resultant uint256 is less than the maxSafeDepositId (i.e.
   // the maximum uint32 value) which makes it possible that an unsafeDepositV3's depositId can collide with a safe
@@ -380,3 +386,8 @@ export async function findFillBlock(
 
   return lowBlockNumber;
 }
+
+// Determines if the input address (either a bytes32 or bytes20) is the zero address.
+export function isZeroAddress(address: string): boolean {
+  return address === ZERO_ADDRESS || address === ZERO_BYTES;
+}
diff --git a/src/utils/ValidatorUtils.ts b/src/utils/ValidatorUtils.ts
index c1a56e6d..9806bab4 100644
--- a/src/utils/ValidatorUtils.ts
+++ b/src/utils/ValidatorUtils.ts
@@ -8,7 +8,7 @@ const HexValidator = define<string>("HexValidator", (v) => ethersUtils.isHexStri
 const BigNumberValidator = define<BigNumber>("BigNumberValidator", (v) => BigNumber.isBigNumber(v));
 
 const V3DepositSchema = object({
-  depositId: Min(integer(), 0),
+  depositId: BigNumberValidator,
   depositor: AddressValidator,
   recipient: AddressValidator,
   inputToken: AddressValidator,
diff --git a/test/SpokePoolClient.ValidateFill.ts b/test/SpokePoolClient.ValidateFill.ts
index f9c91a5d..b342dacc 100644
--- a/test/SpokePoolClient.ValidateFill.ts
+++ b/test/SpokePoolClient.ValidateFill.ts
@@ -2,6 +2,8 @@ import { DepositWithBlock, FillStatus, FillType } from "../src/interfaces";
 import { SpokePoolClient } from "../src/clients";
 import {
   bnOne,
+  bnZero,
+  toBN,
   InvalidFill,
   fillStatusArray,
   relayFillStatus,
@@ -299,7 +301,7 @@ describe("SpokePoolClient: Fill Validation", function () {
 
     // Throws when low < high
     await assertPromiseError(
-      getBlockRangeForDepositId(0, 1, 0, 10, spokePoolClient1),
+      getBlockRangeForDepositId(bnZero, 1, 0, 10, spokePoolClient1),
       "Binary search failed because low > high"
     );
 
@@ -309,7 +311,7 @@ describe("SpokePoolClient: Fill Validation", function () {
     // Searching for deposit ID 0 with 10 max searches should return the block range that deposit ID 0 was mined in.
     // Note: the search range is inclusive, so the range should include the block that deposit ID 0 was mined in.
     const searchRange0 = await getBlockRangeForDepositId(
-      0,
+      bnZero,
       spokePool1DeploymentBlock,
       spokePoolClient1.latestBlockSearched,
       10,
@@ -326,7 +328,7 @@ describe("SpokePoolClient: Fill Validation", function () {
     // Where correct block is the block that the deposit ID incremented to the target.
     // So the correct block for deposit ID 1 is the block that deposit ID 0 was mined in.
     const searchRange1 = await getBlockRangeForDepositId(
-      1,
+      bnOne,
       spokePool1DeploymentBlock,
       spokePoolClient1.latestBlockSearched,
       10,
@@ -339,7 +341,7 @@ describe("SpokePoolClient: Fill Validation", function () {
     // Searching for deposit ID 2 that doesn't exist yet should throw.
     await assertPromiseError(
       getBlockRangeForDepositId(
-        2,
+        toBN(2),
         spokePool1DeploymentBlock,
         spokePoolClient1.latestBlockSearched,
         10,
@@ -381,14 +383,14 @@ describe("SpokePoolClient: Fill Validation", function () {
     // will never equal any of the target IDs (e.g. 3,4,5) because multiple deposits were mined in the same block,
     // incrementing numberOfDeposits() atomically from 2 to 6.
     const searchRange3 = await getBlockRangeForDepositId(
-      3,
+      toBN(3),
       spokePool1DeploymentBlock,
       spokePoolClient1.latestBlockSearched,
       10,
       spokePoolClient1
     );
     const searchRange4 = await getBlockRangeForDepositId(
-      4,
+      toBN(4),
       spokePool1DeploymentBlock,
       spokePoolClient1.latestBlockSearched,
       10,
@@ -397,7 +399,7 @@ describe("SpokePoolClient: Fill Validation", function () {
 
     await assertPromiseError(
       getBlockRangeForDepositId(
-        5,
+        toBN(5),
         spokePool1DeploymentBlock,
         spokePoolClient1.latestBlockSearched,
         10,
@@ -436,7 +438,7 @@ describe("SpokePoolClient: Fill Validation", function () {
       const increment = Math.max(0, Math.floor((Math.random() - 0.5) * 10));
       depositIds[i] = depositIds[i - 1] + increment;
     }
-    fuzzClient.setDepositIds(depositIds);
+    fuzzClient.setDepositIds(depositIds.map(toBN));
     fuzzClient.setLatestBlockNumber(initHigh + 1);
 
     for (let i = 0; i < testIterations; i++) {
@@ -445,7 +447,7 @@ describe("SpokePoolClient: Fill Validation", function () {
 
       // Randomize max # of searches.
       const maxSearches = Math.floor(Math.random() * 19) + 1;
-      const results = await getBlockRangeForDepositId(target, initLow, initHigh, maxSearches, fuzzClient);
+      const results = await getBlockRangeForDepositId(toBN(target), initLow, initHigh, maxSearches, fuzzClient);
 
       // The "correct" block is the first block whose previous block's deposit ID is greater than
       // or equal to the target and whose deposit ID count is greater than the target.
diff --git a/test/utils/utils.ts b/test/utils/utils.ts
index 569b37a3..08e4782e 100644
--- a/test/utils/utils.ts
+++ b/test/utils/utils.ts
@@ -362,7 +362,7 @@ export async function depositV3(
   const { blockNumber, transactionHash, transactionIndex, logIndex } = lastEvent!;
 
   return {
-    depositId: args!.depositId,
+    depositId: toBN(args!.depositId),
     originChainId: Number(originChainId),
     destinationChainId: Number(args!.destinationChainId),
     depositor: args!.depositor,
@@ -403,7 +403,7 @@ export async function requestV3SlowFill(
   const { blockNumber, transactionHash, transactionIndex, logIndex } = lastEvent!;
 
   return {
-    depositId: args.depositId,
+    depositId: toBN(args.depositId),
     originChainId: Number(args.originChainId),
     destinationChainId,
     depositor: args.depositor,
@@ -443,7 +443,7 @@ export async function fillV3Relay(
   const { blockNumber, transactionHash, transactionIndex, logIndex } = lastEvent!;
 
   return {
-    depositId: args.depositId,
+    depositId: toBN(args.depositId),
     originChainId: Number(args.originChainId),
     destinationChainId,
     depositor: args.depositor,
@@ -539,7 +539,7 @@ export function buildDepositForRelayerFeeTest(
 
   const currentTime = getCurrentTime();
   return {
-    depositId: bnUint32Max.toNumber(),
+    depositId: bnUint32Max,
     originChainId: 1,
     destinationChainId: 10,
     depositor: randomAddress(),
diff --git a/test/validatorUtils.test.ts b/test/validatorUtils.test.ts
index 8d77225d..05eff465 100644
--- a/test/validatorUtils.test.ts
+++ b/test/validatorUtils.test.ts
@@ -3,7 +3,7 @@ import { utils, interfaces } from "../src";
 import { ZERO_ADDRESS } from "../src/constants";
 import { randomAddress, toBN } from "./utils";
 import { cloneDeep } from "lodash";
-import { objectWithBigNumberReviver } from "../src/utils";
+import { objectWithBigNumberReviver, bnOne } from "../src/utils";
 import { Deposit } from "../src/interfaces";
 
 describe("validatorUtils", () => {
@@ -11,7 +11,7 @@ describe("validatorUtils", () => {
     let deposit: interfaces.DepositWithBlock;
     beforeEach(() => {
       deposit = {
-        depositId: 1,
+        depositId: bnOne,
         depositor: ZERO_ADDRESS,
         destinationChainId: 1,
         originChainId: 1,
@@ -90,7 +90,7 @@ describe("validatorUtils", () => {
     });
     it("should successfully rehydrate real deposits", () => {
       const deposits: string[] = [
-        '{"inputAmount":{"type":"BigNumber","hex":"0x038d7ea4c68000"},"outputAmount":{"type":"BigNumber","hex":"0x038d7ea4c68000"},"originChainId":42161,"destinationChainId":10,"exclusivityDeadline":1697088000,"fillDeadline":1697088000,"depositId":1160366,"quoteTimestamp":1697088000,"inputToken":"0x82aF49447D8a07e3bd95BD0d56f35241523fBab1","recipient":"0x525D59654479cFaED622C1Ca06f237ce1072c2AB","depositor":"0x269727F088F16E1Aea52Cf5a97B1CD41DAA3f02D","exclusiveRelayer":"0x269727F088F16E1Aea52Cf5a97B1CD41DAA3f02D","message":"0x","blockNumber":139874261,"transactionIndex":1,"logIndex":1,"transactionHash":"0x4c4273f4cceb288a76aa7d6c057a8e3ab571a19711a59a965726e06b04e6b821","realizedLpFeePct":{"type":"BigNumber","hex":"0x016b90ac8ef5b9"},"outputToken":"0x4200000000000000000000000000000000000006","quoteBlockNumber":18332204}',
+        '{"inputAmount":{"type":"BigNumber","hex":"0x038d7ea4c68000"},"outputAmount":{"type":"BigNumber","hex":"0x038d7ea4c68000"},"originChainId":42161,"destinationChainId":10,"exclusivityDeadline":1697088000,"fillDeadline":1697088000,"depositId":{"type":"BigNumber","hex":"0x11b4ae"},"quoteTimestamp":1697088000,"inputToken":"0x82aF49447D8a07e3bd95BD0d56f35241523fBab1","recipient":"0x525D59654479cFaED622C1Ca06f237ce1072c2AB","depositor":"0x269727F088F16E1Aea52Cf5a97B1CD41DAA3f02D","exclusiveRelayer":"0x269727F088F16E1Aea52Cf5a97B1CD41DAA3f02D","message":"0x","blockNumber":139874261,"transactionIndex":1,"logIndex":1,"transactionHash":"0x4c4273f4cceb288a76aa7d6c057a8e3ab571a19711a59a965726e06b04e6b821","realizedLpFeePct":{"type":"BigNumber","hex":"0x016b90ac8ef5b9"},"outputToken":"0x4200000000000000000000000000000000000006","quoteBlockNumber":18332204}',
       ];
       const rehydratedDeposits = deposits.map((d) => JSON.parse(d, objectWithBigNumberReviver) as Deposit);
       expect(rehydratedDeposits.every(utils.isDepositFormedCorrectly)).to.be.true;