--- a/browser/installer/windows/nsis/installer.nsi
+++ b/browser/installer/windows/nsis/installer.nsi
@@ -16,23 +16,19 @@
 ; 7-Zip provides better compression than the lzma from NSIS so we add the files
 ; uncompressed and use 7-Zip to create a SFX archive of it
 SetDatablockOptimize on
 SetCompress off
 CRCCheck on
 
 RequestExecutionLevel user
 
-; The commands inside this ifdef require NSIS 3.0a2 or greater so the ifdef can
-; be removed after we require NSIS 3.0a2 or greater.
-!ifdef NSIS_PACKEDVERSION
-  Unicode true
-  ManifestSupportedOS all
-  ManifestDPIAware true
-!endif
+Unicode true
+ManifestSupportedOS all
+ManifestDPIAware true
 
 !addplugindir ./
 
 Var TmpVal
 Var InstallType
 Var AddStartMenuSC
 Var AddTaskbarSC
 Var AddQuickLaunchSC
@@ -1152,24 +1148,16 @@ Function .onInit
     ExecShell "open" "${URLSystemRequirements}"
     Quit
   ${EndUnless}
   SetRegView 64
 !endif
 
   ${InstallOnInitCommon} "$(WARN_MIN_SUPPORTED_OSVER_CPU_MSG)"
 
-; The commands inside this ifndef are needed prior to NSIS 3.0a2 and can be
-; removed after we require NSIS 3.0a2 or greater.
-!ifndef NSIS_PACKEDVERSION
-  ${If} ${AtLeastWinVista}
-    System::Call 'user32::SetProcessDPIAware()'
-  ${EndIf}
-!endif
-
   !insertmacro InitInstallOptionsFile "options.ini"
   !insertmacro InitInstallOptionsFile "shortcuts.ini"
   !insertmacro InitInstallOptionsFile "components.ini"
   !insertmacro InitInstallOptionsFile "summary.ini"
 
   WriteINIStr "$PLUGINSDIR\options.ini" "Settings" NumFields "5"
 
   WriteINIStr "$PLUGINSDIR\options.ini" "Field 1" Type   "label"

--- a/browser/installer/windows/nsis/maintenanceservice_installer.nsi
+++ b/browser/installer/windows/nsis/maintenanceservice_installer.nsi
@@ -8,23 +8,19 @@
 ; 7-Zip provides better compression than the lzma from NSIS so we add the files
 ; uncompressed and use 7-Zip to create a SFX archive of it
 SetDatablockOptimize on
 SetCompress off
 CRCCheck on
 
 RequestExecutionLevel admin
 
-; The commands inside this ifdef require NSIS 3.0a2 or greater so the ifdef can
-; be removed after we require NSIS 3.0a2 or greater.
-!ifdef NSIS_PACKEDVERSION
-  Unicode true
-  ManifestSupportedOS all
-  ManifestDPIAware true
-!endif
+Unicode true
+ManifestSupportedOS all
+ManifestDPIAware true
 
 !addplugindir ./
 
 ; Variables
 Var TempMaintServiceName
 Var BrandFullNameDA
 Var BrandFullName
 
@@ -125,24 +121,16 @@ Function .onInit
   ${EndUnless}
 FunctionEnd
 
 Function un.onInit
   ; Remove the current exe directory from the search order.
   ; This only effects LoadLibrary calls and not implicitly loaded DLLs.
   System::Call 'kernel32::SetDllDirectoryW(w "")'
 
-; The commands inside this ifndef are needed prior to NSIS 3.0a2 and can be
-; removed after we require NSIS 3.0a2 or greater.
-!ifndef NSIS_PACKEDVERSION
-  ${If} ${AtLeastWinVista}
-    System::Call 'user32::SetProcessDPIAware()'
-  ${EndIf}
-!endif
-
   StrCpy $BrandFullNameDA "${MaintFullName}"
   StrCpy $BrandFullName "${MaintFullName}"
 FunctionEnd
 
 Section "MaintenanceService"
   AllowSkipFiles off
 
   CreateDirectory $INSTDIR

--- a/browser/installer/windows/nsis/stub.nsi
+++ b/browser/installer/windows/nsis/stub.nsi
@@ -13,23 +13,19 @@
 !verbose 3
 
 SetDatablockOptimize on
 SetCompress off
 CRCCheck on
 
 RequestExecutionLevel user
 
-; The commands inside this ifdef require NSIS 3.0a2 or greater so the ifdef can
-; be removed after we require NSIS 3.0a2 or greater.
-!ifdef NSIS_PACKEDVERSION
-  Unicode true
-  ManifestSupportedOS all
-  ManifestDPIAware true
-!endif
+Unicode true
+ManifestSupportedOS all
+ManifestDPIAware true
 
 !addplugindir ./
 
 Var Dialog
 Var Progressbar
 Var ProgressbarMarqueeIntervalMS
 Var LabelDownloading
 Var LabelInstalling
@@ -347,24 +343,16 @@ Function .onInit
     StrCpy $INSTDIR "${DefaultInstDir64bit}"
   ${Else}
     StrCpy $INSTDIR "${DefaultInstDir32bit}"
   ${EndIf}
 
   ; Require elevation if the user can elevate
   ${ElevateUAC}
 
-; The commands inside this ifndef are needed prior to NSIS 3.0a2 and can be
-; removed after we require NSIS 3.0a2 or greater.
-!ifndef NSIS_PACKEDVERSION
-  ${If} ${AtLeastWinVista}
-    System::Call 'user32::SetProcessDPIAware()'
-  ${EndIf}
-!endif
-
   ; If we have any existing installation, use its location as the default
   ; path for this install, even if it's not the same architecture.
   SetRegView 32
   SetShellVarContext all ; Set SHCTX to HKLM
   ${GetSingleInstallPath} "Software\Mozilla\${BrandFullNameInternal}" $R9
 
   ${If} "$R9" == "false"
   ${AndIf} ${RunningX64}

--- a/browser/installer/windows/nsis/uninstaller.nsi
+++ b/browser/installer/windows/nsis/uninstaller.nsi
@@ -14,23 +14,19 @@
 ; 7-Zip provides better compression than the lzma from NSIS so we add the files
 ; uncompressed and use 7-Zip to create a SFX archive of it
 SetDatablockOptimize on
 SetCompress off
 CRCCheck on
 
 RequestExecutionLevel user
 
-; The commands inside this ifdef require NSIS 3.0a2 or greater so the ifdef can
-; be removed after we require NSIS 3.0a2 or greater.
-!ifdef NSIS_PACKEDVERSION
-  Unicode true
-  ManifestSupportedOS all
-  ManifestDPIAware true
-!endif
+Unicode true
+ManifestSupportedOS all
+ManifestDPIAware true
 
 !addplugindir ./
 
 ; Attempt to elevate Standard Users in addition to users that
 ; are a member of the Administrators group.
 !define NONADMIN_ELEVATE
 
 ; prevents compiling of the reg write logging.
@@ -602,24 +598,16 @@ Function un.onInit
   ; Remove the current exe directory from the search order.
   ; This only effects LoadLibrary calls and not implicitly loaded DLLs.
   System::Call 'kernel32::SetDllDirectoryW(w "")'
 
   StrCpy $LANGUAGE 0
 
   ${un.UninstallUnOnInitCommon}
 
-; The commands inside this ifndef are needed prior to NSIS 3.0a2 and can be
-; removed after we require NSIS 3.0a2 or greater.
-!ifndef NSIS_PACKEDVERSION
-  ${If} ${AtLeastWinVista}
-    System::Call 'user32::SetProcessDPIAware()'
-  ${EndIf}
-!endif
-
   !insertmacro InitInstallOptionsFile "unconfirm.ini"
 FunctionEnd
 
 Function .onGUIEnd
   ${OnEndCommon}
 FunctionEnd
 
 Function un.onGUIEnd

--- a/toolkit/components/maintenanceservice/bootstrapinstaller/maintenanceservice_installer.nsi
+++ b/toolkit/components/maintenanceservice/bootstrapinstaller/maintenanceservice_installer.nsi
@@ -8,23 +8,19 @@
 ; 7-Zip provides better compression than the lzma from NSIS so we add the files
 ; uncompressed and use 7-Zip to create a SFX archive of it
 SetDatablockOptimize on
 SetCompress off
 CRCCheck on
 
 RequestExecutionLevel admin
 
-; The commands inside this ifdef require NSIS 3.0a2 or greater so the ifdef can
-; be removed after we require NSIS 3.0a2 or greater.
-!ifdef NSIS_PACKEDVERSION
-  Unicode true
-  ManifestSupportedOS all
-  ManifestDPIAware true
-!endif
+Unicode true
+ManifestSupportedOS all
+ManifestDPIAware true
 
 !addplugindir ./
 
 ; Variables
 Var TempMaintServiceName
 Var BrandFullNameDA
 Var BrandFullName
 
@@ -122,24 +118,16 @@ Function .onInit
   ${EndUnless}
 FunctionEnd
 
 Function un.onInit
   ; Remove the current exe directory from the search order.
   ; This only effects LoadLibrary calls and not implicitly loaded DLLs.
   System::Call 'kernel32::SetDllDirectoryW(w "")'
 
-; The commands inside this ifndef are needed prior to NSIS 3.0a2 and can be
-; removed after we require NSIS 3.0a2 or greater.
-!ifndef NSIS_PACKEDVERSION
-  ${If} ${AtLeastWinVista}
-    System::Call 'user32::SetProcessDPIAware()'
-  ${EndIf}
-!endif
-
   StrCpy $BrandFullNameDA "${MaintFullName}"
   StrCpy $BrandFullName "${MaintFullName}"
 FunctionEnd
 
 Section "MaintenanceService"
   AllowSkipFiles off
 
   CreateDirectory $INSTDIR