What's the difference? Quoted below is the Microsoft patch notes - but they only list which files are modified. There is no information whatsoever on what the actual changes / bugfixes were. Does anyone know?

====================================================================== Microsoft(R) Product Support Services Application Note […]
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======================================================================
Microsoft(R) Product Support Services Application Note (Text File)
WW0981: WINDOWS(TM) 3.11 REFRESH FILES
======================================================================
Revision Date: 2/94
1 Disk Included

The following information applies to the version Windows 3.11 update
for Windows 3.10 users.

-----------------------------------------------------------------------
| INFORMATION PROVIDED IN THIS DOCUMENT AND ANY SOFTWARE THAT MAY |
| ACCOMPANY THIS DOCUMENT (collectively referred to as an Application |
| Note) IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER |
| EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED |
| WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR |
| PURPOSE. The user assumes the entire risk as to the accuracy and |
| the use of this Application Note. This Application Note may be |
| copied and distributed subject to the following conditions: 1) All |
| text must be copied without modification and all pages must be |
| included; 2) If software is included, all files on the disk(s) |
| must be copied without modification (the MS-DOS(R) utility |
| diskcopy is appropriate for this purpose); 3) All components of |
| this Application Note must be distributed together; and 4) This |
| Application Note may not be distributed for profit. |
| |
| Copyright (C) 1994 Microsoft Corporation. All Rights Reserved. |
| Microsoft and MS-DOS are registered trademarks and Windows is a |
| trademark of Microsoft Corporation. |
|---------------------------------------------------------------------|

ADDENDUM TO THE MICROSOFT SOFTWARE LICENSE AGREEMENT
====================================================
FOR MICROSOFT WINDOWS OPERATING SYSTEM VERSION 3.10
===================================================

The files provided in this Application Note are intended to replace
the corresponding files provided with Microsoft Windows 3.10. Upon
installation, these files become a part of the Windows operating
system and are subject to the same license terms and conditions as the
Windows 3.10 product you previously acquired from Microsoft
Corporation. Any other use of these files is prohibited.

MICROSOFT WINDOWS VERSION 3.11 FILES
====================================

This Application Note includes updated versions of eight core Windows
3.10 files. To update these files to version 3.11, follow the
procedure below that is appropriate to your configuration.

To update a local installation of Windows 3.10 to Windows 3.11
--------------------------------------------------------------

1. Quit Microsoft Windows.

2. Create a backup directory. For example, to create a backup
directory off the root of drive C, type MD C:\BACKUP at the MS-DOS
command prompt and then press ENTER.

3. Copy the files listed below from your Windows SYSTEM subdirectory
to the backup directory or a floppy disk.

COMMDLG.DLL
GDI.EXE
KRNL386.EXE
PSCRIPT.DRV
UNIDRV.DLL
SHELL.DLL
USER.EXE

To do this, use the following syntax

copy <drive>:\<windir>\system\<filename> <drive>:\<backdir>

where <drive> is your hard disk drive, <windir> is your Windows
directory, <filename> is the file you are copying, and <backdir> is
your backup directory.

For example, if your hard disk drive is C, your Windows directory
is named WINDOWS, and you are copying COMMDLG.DLL, type the
following:

copy c:\windows\system\commdlg.dll c:\backup

Repeat this command for the remaining files.

4. Insert the enclosed WW0981 disk in the appropriate floppy disk
drive. At the MS-DOS command prompt, type the following and then
press ENTER

copy <drive>:\*.* <destination>

where <drive> is your floppy disk drive and <destination> is your
Windows SYSTEM subdirectory.

For example:

copy a:\*.* c:\windows\system

5. If you use Novell NetWare connectivity, do the following:

a. Use a text editor (such as Windows Notepad) to open your
SYSTEM.INI file, which is located in your Windows directory.

b. In the [386Enh] section, change DEVICE=*VTD to DEVICE=VTDA.386.

c. Save the file and quit the text editor.

To update a network installation of Windows 3.10 to Windows 3.11
----------------------------------------------------------------

1. Determine the location of your SYSTEM.INI file and the network
share that contains your shared Windows files. For example, if the
network drive containing your Windows program files is Q, the
location of your shared Windows files may be Q:\WINSHARE and your
user directory may be Q:\USER\<YOURNAME> (or your user directory
may be located on your local hard disk drive).

2. Quit Microsoft Windows.

3. Create a backup directory. For example, to create a backup
directory off the root of drive C, type MD C:\BACKUP at the MS-DOS
command prompt and then press ENTER.

4. Copy the following files from the network share to the backup
directory on your hard disk drive using the following syntax at the
MS-DOS command prompt and then press ENTER

copy <netdrive>:\<netshare>\<filename> <harddrive>:\<backdir>

where <netdrive> is the network drive,<netshare> is the network
share containing your SYSTEM.INI file, <filename> is the file you
are copying, <harddrive> is your hard disk drive, and <backdir> is
your backup directory.

For example, if your network drive is Q, the network share is
WINSHARE, the file you want to copy is COMMDLG.DLL, your hard disk
drive is C, and your backup directory is called BACKUP, type the
following:

copy q:\winshare\commdlg.dll c:\backup

Repeat this command for the remaining files:

COMMDLG.DLL
GDI.EXE
KRNL386.EXE
PSCRIPT.DRV
UNIDRV.DLL
SHELL.DLL
USER.EXE

5. Remove the read-only file attributes on the shared Windows files
using the MS-DOS ATTRIB command.

6. Insert the enclosed WW0981 disk in the appropriate floppy disk
drive. At the MS-DOS command prompt, type the following and then
press ENTER

copy <drive>:\*.* <destination>

where <drive> is your floppy disk drive and <destination> is the
network drive and share.

For example:

copy a:\*.* q:\winshare

7. Reset the read-only file attributes on the shared Windows files
using the MS-DOS ATTRIB command.

8. If you use Novell NetWare connectivity, do the following:

a. Use a text editor (such as Windows Notepad) to open your
SYSTEM.INI file.

b. In the [386Enh] section, change DEVICE=*VTD to DEVICE=VTDA.386.

c. Save the file and quit the text editor.