To know how to use these files, read

For each edition, only the most recent installer is stored here.

The release date is not part of the filename, but it is indicated at the
root of the ISO file as SLINT_DATE. You can check it like it e.g.:
  mount <file>.iso /mnt
  cat /mnt/SLINT_DATE
There is also a README:
You can then umount the ISO file:
  umount /mnt

WARNING: These installers do not include Slackware packages.

If you prefer a DVD + USB ISO image that contain a  Slint installer and
all Slackware packages for Slackware 14.1 (32-bit or 64-bit), see here:
 NameLast modifiedSizeDescription

[DIR]Parent Directory  -  
[TXT]Restore_an_USB_stick.txt2013-11-11 17:08 923  
[ISO]slint-13.37.iso2015-12-20 11:42 37M 
[TXT]slint-13.37.iso.md52015-12-20 19:51 50  
[ISO]slint-14.0.iso2015-12-20 11:43 49M 
[TXT]slint-14.0.iso.md52015-12-20 19:51 49  
[ISO]slint-14.1.iso2015-12-20 11:43 67M 
[TXT]slint-14.1.iso.md52015-12-20 19:51 49  
[ISO]slint64-13.37.iso2015-12-20 11:52 28M 
[TXT]slint64-13.37.iso.md52015-12-20 19:51 52  
[ISO]slint64-14.0.iso2015-12-20 11:52 38M 
[TXT]slint64-14.0.iso.md52015-12-20 19:51 51  
[ISO]slint64-14.1.iso2015-12-20 11:53 57M 
[TXT]slint64-14.1.iso.md52015-12-20 19:51 51