How do you upgrade buildings in Elvenar?

In the game Elvenar, upgrading buildings is a crucial aspect of gameplay that allows for enhancement of production and advancement within the game. To upgrade a building, one must first ensure that the requisite research has been conducted in the technology tree. Once unlocked, the player can then select the building they wish to upgrade and click on the "Upgrade" button, typically represented by an upwards arrow or a set of construction tools. Prior to confirming the upgrade, it is important to check if enough resources are available and if there is sufficient space for the building's increased footprint. The upgrade process takes time to complete, but this duration can be reduced by using time boosters or diamonds, which are premium in-game currencies. Upgrading buildings not only improves their output and functionality but also contributes to the aesthetic development of the city as buildings become more visually elaborate with each level.