My details are
Model Netgear WNDR4700/WNDR4720 Series
Firmware Version LEDE Reboot 17.01.4 r3560-79f57e422d / LuCI lede-17.01 branch (git-17.290.79498-d3f0685)
Kernel Version 4.4.92
Local Time Fri Feb 16 14:28:30 2018
Uptime 18d 2h 20m 42s
I want to check is there any new update or not how can I find that, I use to to download from here
How to check which version, I have installed
I think I am using
WNDR4700-squashfs-sysupgrade.tar d8edf7046a9ce31e94fb67f6e3a03a3afea4eaf6719a4da21554300501901024 4630.0 KB Wed Oct 18 18:27:44 2017
but how to be sure?
17.01.4 is still the latest stable release version.
If your firmware file name does not include a version number, it is probably a snapshot build.
The version number is reported on the Status-> Overview page of LuCI, or on the signon message when you log in by ssh. That message is stored in /etc/banner.
You already know how to do that:
there is no date in versioning so the problem with relating with https://downloads.lede-project.org/releases/17.01.4/targets/apm821xx/nand/
WNDR4720 is supported as the only difference between the WNDR4700 and WNDR4720 is packaging. The WINDR4700 comes without a disk drive and the WNDR4720 includes a disk drive.
I guess it is impossible to know "release date" from this string "Firmware Version LEDE Reboot 17.01.4 r3560-79f57e422d / LuCI lede-17.01 branch (git-17.290.79498-d3f0685)"
It it's branded 17.01.4 that can be only one thing: that specific release which I think was in October of 2017.
Depends on how you look at it. If you search the forum you'll find the announcement eventually: LEDE v17.01.4 service release.
A good indicator would be the kernel compilation date, which gets printed if you call
# uname -a, e.g.:
# uname -a
Linux lede 4.4.115 #0 SMP Wed Feb 14 22:57:17 2018 mips GNU/Linux
Here, you can see this kernel (and the matching firmware) was compiled on February 14th (self-compiled from the 17.01 git, in case you wonder about the higher number).
However, you shouldn't focus too much on the date. What's important is the git hash (ie 79f57e422d), which allows you to retrieve the same 'state' from the git tree in case you'd like to build yourself. That's more important than the actual release date. The release number itself is linear, so - there's no 17.01.5, which means you're on the latest stable release.