Capacity Upgrade 4: It is placed on a shelf, in a storage area under the stairs.
Capacity Upgrade 5: It is located inside a locked room with a Ravens symbol to decipher.
Firing Speed Upgrade 5: Can be looted of an enraged super zombie during the last bit of mission 15.
Firing Speed Upgrade 6: Situated in the omega barracks just behind the C4 trash pile.
Palace Underground (Queen’s Quarter)
Spread Upgrade 5: Situated behind the open vault door.
Buckingham Palace (Interior)
Firepower upgrade 6: It is located in the crawl space between the fiery state room and the long blue corridor.
Firepower Upgrade 7: It can be found in the hallway and the stairs area. It can be looted off a super zombie there.
Buckingham Palace (Kitchens)
Spread Upgrade 6: It is among the scattered trolleys in the kitchens pantry.
Fire Speed Upgrade 7: Situated in the tiny storage space which can be accessed by blowing up the C4 blocking the entrance.
Brick Lane Flats (Old Brick Warehouses)
Capacity Upgrade 6: It is located on the top floor office behind the raven’s keypad door.
Spread Upgrade 7: Situated behind the locked door in a small storage room off the warehouse loading bay.
Firing Speed Upgrade 8: It can be looted off an enraged super zombie behind the C4 trash wall. It is in the second warehouse.
Brick Lane Flats (Ron Freedman’s Flat)
Firepower Upgrade 8: Situated in the Freedman’s office. It is placed inside the safe.
Tower of London (Tower Pier)
Spread Upgrade 8: It is on the tugboat. You can get to it with Dee’s letter#6 and a M4 shotgun.
Firing Speed Upgrade 8: It can be looted of an enraged super zombie on the tugboat.
Tower of London (Bloody Tower)
Capacity Upgrade 7: Situated in the water dungeon on a small alcove.
Spread Upgrade 9: It is located in the corner of Raven’s hidden chamber. It is held by a suit of armor.
Spitalfields Green (Quaker Park)
Capacity Upgrade 8: It is located behind the metal fencing. It is by the a corpse with Dee’s letter, across from the park.
Firepower Upgrade 9: Can be looted of the enraged super zombie in the park.
Speed Upgrade 10: In the storage room behind the C4 wall. It can be accessed by the hole in the brick wall in one corner of the park.
Firing Speed Upgrade 10: Situated on the upper balcony, which is overlooking the alleyways below.
Spitalfields Green (Shoreditch Petrol Station)
Capacity Upgrade 9: It can be found behind the gate near the petrol station.
Firepower Upgrade 10: It is located in the hallway behind the black light coded keypad door. It is accessed via the ladder.
Baconfields (Darwin Yard)
Capacity Upgrade 10: It is located in the locked shed. In there is Magnum pistol and Dee’s letter# 17 too.
Spread Upgrade 11: It is in the connecting rooms close to the manhole.
Spread Upgrade 12: Can be looted of an enraged super zombie in the wasteland.
Firing Speed Upgrade 11: It is found in the bushes below the massive motorway pillar. It is near the huts.
Baconfields (Brick Lane Community Nursery)
Firepower Upgrade 11: It is situated in the lower basement keypad storage room. There is also the UMP 45 and C4 as well.
St. George’s Church (Catacombs)
Capacity Upgrade 11: Can be looted off an enraged super zombie in the main corridor.
Spread Upgrade 13: Situated in the toilets behind the C4 trash pile.
Firing Speed Upgrade 12: It is located in the small keypad storage room near the CCTV junction box.
St. George’s Church (Crypt)
Firepower Upgrade 12: It is placed in the corner of the waterlogged lower area.
St. George’s Church (Arena Courtyard)
Firepower Upgrade 13: Situated behind the locked gate close to the exit ladder.