diff --git a/.cipd_impl.ps1 b/.cipd_impl.ps1
index eb83751315..ce8091413f 100644
--- a/.cipd_impl.ps1
+++ b/.cipd_impl.ps1
@@ -11,19 +11,29 @@
 #     -VersionFile ./cipd_client_version
 # file _cipd.exe
 
-Param(
-  # Path to download the CIPD binary to.
-  [parameter(Mandatory=$true)][string]$CipdBinary,
-  # E.g. "https://chrome-infra-packages.appspot.com".
-  [parameter(Mandatory=$true)][string]$BackendURL,
-  # Path to the cipd_client_version file with the client version.
-  [parameter(Mandatory=$true)][string]$VersionFile
+param(
+    # Path to download the CIPD binary to.
+    [Parameter(Mandatory = $true)]
+    [string]
+    $CipdBinary,
+    
+    # CIPD platform to download the client for.
+    [string]
+    $Platform = "windows-amd64",
+
+    # E.g. "https://chrome-infra-packages.appspot.com".
+    [Parameter(Mandatory = $true)]
+    [string]
+    $BackendURL,
+
+    # Path to the cipd_client_version file with the client version.
+    [Parameter(Mandatory = $true)]
+    [string]
+    $VersionFile
 )
 
 $DepotToolsPath = Split-Path $MyInvocation.MyCommand.Path -Parent
 
-$Platform = "windows-amd64"
-
 # Put depot_tool's git revision into the user agent string.
 try {
   $DepotToolsVersion = &git -C $DepotToolsPath rev-parse HEAD 2>&1
diff --git a/cipd.bat b/cipd.bat
index e0312921e7..d44f9ad625 100644
--- a/cipd.bat
+++ b/cipd.bat
@@ -8,6 +8,35 @@ setlocal
 set CIPD_BACKEND=https://chrome-infra-packages.appspot.com
 set VERSION_FILE=%~dp0cipd_client_version
 set CIPD_BINARY=%~dp0.cipd_client.exe
+set CIPD_PLATFORM=windows-amd64
+set PLATFORM_OVERRIDE_FILE=%~dp0.cipd_client_platform
+
+:: Uncomment to recognize arm64 by default.
+:: if %PROCESSOR_ARCHITECTURE%==ARM64 (
+::   set CIPD_PLATFORM=windows-arm64
+:: )
+
+:: A value in .cipd_client_platform overrides the "guessed" platform.
+if exist "%PLATFORM_OVERRIDE_FILE%" (
+  for /F usebackq %%l in ("%PLATFORM_OVERRIDE_FILE%") do (
+    set CIPD_PLATFORM=%%l
+  )
+)
+
+:: Nuke the existing client if its platform doesn't match what we want now. We
+:: crudely search for a CIPD client package name in the .cipd_version JSON file.
+:: It has only "instance_id" as the other field (looking like a base64 string),
+:: so mismatches are very unlikely.
+set INSTALLED_VERSION_FILE=%~dp0.versions\.cipd_client.exe.cipd_version
+findstr /m "infra/tools/cipd/%CIPD_PLATFORM%" "%INSTALLED_VERSION_FILE%" 2>nul
+if %ERRORLEVEL% neq 0 (
+  if exist "%INSTALLED_VERSION_FILE%" (
+    echo Detected CIPD client platform change to %CIPD_PLATFORM%. 1>&2
+    echo Deleting the existing client to trigger the bootstrap... 1>&2
+    del "%CIPD_BINARY%"
+    del "%INSTALLED_VERSION_FILE%"
+  )
+)
 
 if not exist "%CIPD_BINARY%" (
   call :CLEAN_BOOTSTRAP
@@ -50,6 +79,7 @@ echo.>"%~dp0.cipd_impl.ps1:Zone.Identifier"
 powershell -NoProfile -ExecutionPolicy RemoteSigned ^
     -File "%~dp0.cipd_impl.ps1" ^
     -CipdBinary "%CIPD_BINARY%" ^
+    -Platform "%CIPD_PLATFORM%" ^
     -BackendURL "%CIPD_BACKEND%" ^
     -VersionFile "%VERSION_FILE%" ^
   <nul
diff --git a/cipd_client_version b/cipd_client_version
index b480fd4c9f..358ebccd74 100644
--- a/cipd_client_version
+++ b/cipd_client_version
@@ -1 +1 @@
-git_revision:89ada246fcbf10f330011e4991d017332af2365b
+git_revision:81e5cdad29bb4c7aaad98c843637513db3155b0d
diff --git a/cipd_client_version.digests b/cipd_client_version.digests
index 2b3abae1e3..62d682e4d1 100644
--- a/cipd_client_version.digests
+++ b/cipd_client_version.digests
@@ -1,24 +1,25 @@
 # This file was generated by
 #
 #  cipd selfupdate-roll -version-file cipd_client_version \
-#      -version git_revision:89ada246fcbf10f330011e4991d017332af2365b
+#      -version git_revision:81e5cdad29bb4c7aaad98c843637513db3155b0d
 #
 # Do not modify manually. All changes will be overwritten.
 # Use 'cipd selfupdate-roll ...' to modify.
 
-aix-ppc64       sha256  bf60b679afae76b7d52f46453dc67af6938438c9c8543b40d49f62eb6edb7376
-linux-386       sha256  7f264198598af2ef9d8878349d33c1940f1f3739e46d986962c352ec4cce2690
-linux-amd64     sha256  2ada6b46ad1cd1350522c5c05899d273f5c894c7665e30104e7f57084a5aeeb9
-linux-arm64     sha256  96eca7e49f6732c50122b94b793c3a5e62ed77bce1686787a8334906791b4168
-linux-armv6l    sha256  06394601130652c5e1b055a7e4605c21fc7c6643af0b3b3cac8d2691491afa81
-linux-mips64    sha256  f3eda6542b381b7aa8f582698498b0e197972c894590ec35f18faa467c868f5c
-linux-mips64le  sha256  74229ada8e2afd9c8e7c58991126869b2880547780d4a197a27c1dfa96851622
-linux-mipsle    sha256  2f3c18ec0ad48cd44a9ff39bb60e9afded83ca43fb9c7a5ea9949f6fdd4e1394
-linux-ppc64     sha256  79425c0795fb8ba12b39a8856bf7ccb853e85def4317aa6413222f307d4c2dbd
-linux-ppc64le   sha256  f9b3d85dde70f1b78cd7a41d2477834c15ac713a59317490a4cdac9f8f092325
-linux-riscv64   sha256  bd695164563a66e8d3799e8835f90a398fbae9a4eec24e876c92d5f213943482
-linux-s390x     sha256  6f501af80541e733fda23b4208a21ea05919c95d236036a2121e6b6334a2792c
-mac-amd64       sha256  41d05580c0014912d6c32619c720646fd136e4557c9c7d7571ecc8c0462733a1
-mac-arm64       sha256  dc672bd16d9faf277dd562f1dc00644b10c03c5d838d3cc3d3ea29925d76d931
-windows-386     sha256  fa6ed0022a38ffc51ff8a927e3947fe7e59a64b2019dcddca9d3afacf7630444
-windows-amd64   sha256  b5423e4b4429837f7fe4d571ce99c068aa0ccb37ddbebc1978a423fd2b0086df
+aix-ppc64       sha256  94f91ea0510c321e05b2aeb91384aa0ef408502111eba3139f96233889830594
+linux-386       sha256  793e89413fbf76be97b5b40d96326e67cd8a52b807c450d0a0bf80eda841db9b
+linux-amd64     sha256  ee6be8d78509aafa583310548f08a4f3f63e7ee7aebffd1b139db4c9d07ab3ed
+linux-arm64     sha256  5ecf44dec64fdc90272096512fe1fc0e6df7472fad4a6ebc68041d4270e80882
+linux-armv6l    sha256  9acb7d3b96c85dbae3927a9b8228732d6b885ebbfeaa1e4d010dea7a3a74c7c6
+linux-mips64    sha256  ac678cca38e075ddf7629ff8bc97d7ff8a89962debd1f76d048ca33cbff2207e
+linux-mips64le  sha256  f90bcf95e4cf123f5465251beb53e137a1e9ba12a6636166e40137c62697e11b
+linux-mipsle    sha256  96a7a5e891b3fb38f0563a9d20a58b5bcda6a53f6fddf199083bd9f2cad9eec3
+linux-ppc64     sha256  a96529881650b24095b2147497a8e56aa24b4d7f3a27ec97d2f114731497f353
+linux-ppc64le   sha256  e90002d416080cc2f0e3cd9951c6c668836ca9f5e49fb67718146a782f66023b
+linux-riscv64   sha256  ab0598645341f5a9cf874918b382947fb4fc36c0d5f86c70477feb65d47f5d4d
+linux-s390x     sha256  e7e4fa8f1b60f9280f4b11a5a4be3acc7bbde923462bbd6f22400e0adb7892be
+mac-amd64       sha256  0707cb69e608d6b82b643ef898ac8b5c67abfa1cc244fe04f89cafd101d3c9c7
+mac-arm64       sha256  ee5983b13e382dde223edb6f395ae92df2d1744094a43d54bfbad26fc835cecb
+windows-386     sha256  9f6c95d71d71041df9254c6efa181f763e6589697c59489b76d72b1444eae57f
+windows-amd64   sha256  ddba94f29fe5281f4b9ef416effebd9f31e6910a12d66d8978d0aa0406a9c173
+windows-arm64   sha256  86da354a76a943c85146ee31f0f161518edada359b48179643bf3ad1aaad3bda