
Samsung Galaxy S 4 (Canada)
The latest firmware for Samsung Galaxy S 4 (Canada) (SGH-I337M) is I337MUMUGPI2 with Jelly(Android Bean), released on September 8, 2016 for 3 regions (CSC). Every official firmware build for SGH-I337M, newest first: one row per build with all regions (CSC) that received it.
Each firmware build has its own page at https://samfirm.shop/build/{PDA}, where {PDA} is the build number from the list above. Example: https://samfirm.shop/build/I337MUMUGPI2
All 34 builds in our database run Android 4.4.2 (KitKat). The newest build, I337MUMUGPI2, was released on September 8, 2016. No new build has appeared for 123 months, so regular updates for this model have most likely ended.

SGH-I927

SGH-S730M

SGH-T999N

SGH-T989D

SGH-T859

SGH-T599V

SGH-I757M

SGH-I747
The newest firmware for SGH-I337M runs Android 4.4.2 (KitKat): build I337MUMUGPI2, released on September 8, 2016.
The latest build for SGH-I337M, I337MUMUGPI2, was released on September 8, 2016 (10 years ago).
SGH-I337M has had no new firmware for 123 months, so regular updates have most likely ended.
Yes, all firmware files for SGH-I337M are 100% official, original, and obtained directly from Samsung servers.
To flash SGH-I337M, you need to download the appropriate firmware, put your device into Download Mode, and use the Odin tool to load the BL, AP, CP, and CSC files.
Downgrading is only possible if the bootloader version (binary bit) of the old firmware matches the current one. Always check the binary version before flashing SGH-I337M.