As has been noted, W.E. Patt. '25 was designated as Web Equipment, Pattern 1919 in Canada. To distinguish it from the OTHER Patt. '19, I've tried to consistently refer to it as Pattern 1925. However, the title and text of Canadian Militia Order 500 are quoted as written, so you may well find both designations in the same paragraph.
Haversack


The Pattern 1925 Haversack introduced into Canada with the Web Equipment, Pattern 1919, under Militia Order 500, dated 28th September 1928. It is similar to the Patt. '19 Haversack, but all fittings on the rear have been deleted - this Haversack is designed to be suspended from the Braces only, and does not have provision to be worn on the back. Like the Patt. '14 and Patt. '19 Haversacks, it is approximately 9-inches tall by 11-inches wide, and is tapered in profile, deeper (4-inches) at the bottom than at the top (2-inches). This example is maker marked "M.E. Co." and dated 1927.
Rucksack, Top Part

The Pattern 1925 Rucksack, Top Part, introduced into Canada with the Web Equipment, Pattern 1919, under Militia Order 500, dated 28th September 1928. There are two horizontal 3/4 inch straps on the face of the Rucksack, as shown in the picture far left. These are equipment straps, and are used to carry additional items such as axes, shovels, helmets, etc. The Rucksack, Top Part has integral 2-inch shoulder straps that loop over the shoulder on top of the Braces and connect to the buckles at the top of the Cartridge carriers. Each shoulder strap has a 3/4-inch side strap as well.These connect to buckles on the the bottom of the Rucksack, Top Part, when it is worn alone, and to buckles on the bottom of the Rucksack, Bottom Part, when both halves are worn. On the first version of the Rucksack, the side strap on the left is attached to the shoulder strap buckle, while one on the left is detachable. Instead of being sewn in place, it is attached to the shoulder strap buckle with a flat brass hook This allows the Rucksack to be more easily removed. For a discussion of this Rucksack Supporting Strap (or Kicking Strap, as it was sometimes called in service), see the Web Equipment, Pattern 1925 (Blue-Grey) Belts and Straps Section. This example is maker marked "M.E. Co." and dated 1927.
Rucksack, Bottom Part
The Pattern 1925 Rucksack, Bottom Part, introduced into Canada with the Web Equipment, Pattern 1919, under Militia Order 500, dated 28th September 1928. The Rucksack, Bottom Part attaches to the Top Part to provide additional carrying capacity. Unlike the Rucksack, Top Part, it cannot be worn alone. The intention is that non-essential items of kit are carried in the Bottom Part. In troop movements, the Rucksack, Bottom Part, can be removed from the Top Part, closed, and carried by mechanised transport. Although the Bottom Part can be attached to the Top Part when closed, it is normally attached open. This allows items to be easily removed without disconnecting the two halves. I do not have a khaki example of the Rucksack, Bottom Part, but there is a blue-grey one shown in the section on Blue-Grey Haversacks and Packs.