I've successfully booted my N1148T-ON HW Version 5 onto the N1100v6.7.1.10 image.  I have been running 0 days, 01h:53m:05s without problem on my slightly complex set of broadcast domains.  The limit is 512, and I'm using maybe 12.  I also have an N1124T-ON HW Version 4 running on the same version.  If Dell could indicate which of the next image versions work on these hardware versions, it would support me in my enterprise.

switch02#show version

Machine Description............... Dell EMC Networking Switch

System Model ID................... N1148T-ON

Machine Type...................... Dell EMC Networking N1148T-ON

Serial Number..................... REDACTED

Manufacturer...................... 0xbc00

Burned In MAC Address............. ALSO REDACTED

System Object ID.................. 1.3.6.1.4.1.674.10895.3082

SOC Version....................... BCM53440_B0

HW Version........................ 5

CPLD Version...................... 7

Image File........................ N1100v6.7.1.10

Software Capability............... Stack Limit = 4, VLAN Limit = 512

unit active backup current-active next-active

---- ----------- ----------- -------------- --------------

1 6.7.1.10 6.7.0.4 6.7.1.10 6.7.1.10

switch0:

switch0#show version

Machine Description............... Dell EMC Networking Switch
System Model ID................... N1124T-ON
Machine Type...................... Dell EMC Networking N1124T-ON
Serial Number..................... REDACTED
Manufacturer...................... 0xbc00
Burned In MAC Address............. ALSO REDACTED
System Object ID.................. 1.3.6.1.4.1.674.10895.3080
SOC Version....................... BCM53440_B0
HW Version........................ 4
CPLD Version...................... 7
Image File........................ N1100v6.7.1.10
Software Capability............... Stack Limit = 4, VLAN Limit = 512

unit active      backup      current-active next-active
---- ----------- ----------- -------------- --------------
1    6.7.1.10    6.4.2.8     6.7.1.10       6.7.1.10

I see that the filename format varies[1] between the 6.7 branch and the 6.8 branch.  The ones that say Dell EMC Networking N1100-ON Series Switches have worked for me, but the ones with format Upgrading Dell Networking N1100-ON Series Switches complain that this hardware will not run this image version.

[1] cjac@cjac11:/tmp$ evince Upgrading\ Dell\ 
Upgrading Dell EMC Networking N1100-ON Series Switches to Version 6.7.1.10.pdf
Upgrading Dell EMC Networking N1100-ON Series Switches to Version 6.7.1.22.pdf
Upgrading Dell Networking N1100-ON Series Switches to Version 6.8.1.2.pdf

I have now tried the N1100v6.7.1.22.stk image.  each of the devices are in the route path for the TCP socket over which I am submitting this post.  

24-port: System Up Time: 0 days, 00h:07m:44s

48-port: System Up Time: 0 days, 00h:08m:16s

I approve of 6.7.1.22[1] in my AS on:

* N1124T-ON HW Version 4

* N1148T-ON HW Version 5

[1] https://www.dell.com/support/home/en-ai/drivers/driversdetails?driverid=xr4v3&oscode=naa&productcode=networking-n1100-series