Builder Hall 4 upgrades cover heroes, buildings, traps, and troops. Star Laboratory max level at BH4: 4.
Max Levels for Buildings
There are 21 upgradable buildings and traps at this level. See the table below for max levels and upgrade counts.
| Building | Max Level | Number of Upgrades |
|---|---|---|
| Air Bombs | 4 | 4 |
| Archer Tower | 4 | 1 |
| Builder Barracks | 6 | 2 |
| Cannon | 4 | 1 |
| Clock Tower | 4 | 4 |
| Crusher | 4 | 1 |
| Double Cannon | 4 | 1 |
| Elixir Collector | 4 | 1 |
| Elixir Storage | 4 | 1 |
| Firecrackers | 4 | 1 |
| Gem Mine | 4 | 1 |
| Gold Mine | 4 | 1 |
| Gold Storage | 4 | 1 |
| Guard Post | 4 | 4 |
| Hidden Tesla | 4 | 1 |
| Mega Mine | 4 | 4 |
| Mine | 4 | 1 |
| Push Trap | 4 | 1 |
| Spring Trap | 2 | 1 |
| Star Laboratory | 4 | 1 |
| Wall | 4 | 1 |
Max Levels for Troops
Builder Base troop levels are gated by the Star Laboratory (max level 4 at BH4).
There are 6 upgradable troops at this level: Baby Dragon, Beta Minion, Bomber, Boxer Giant, Raged Barbarian, and Sneaky Archer. See the table below for max levels and upgrade counts.
| Troop | Max Level | Number of Upgrades |
|---|---|---|
| Baby Dragon | 8 | 7 |
| Beta Minion | 8 | 2 |
| Bomber | 8 | 7 |
| Boxer Giant | 8 | 2 |
| Raged Barbarian | 8 | 2 |
| Sneaky Archer | 8 | 2 |