Most "unblocked" versions found on sites like Google Sites or CodeTorch are fan-made reconstructions or limited browser ports.
Terraria 1.4: "Journey's End" and High-Quality Gameplay Terraria 1.4 terraria 14 unblocked high quality
The most stable and high-quality versions of Terraria 1.4 (and the latest update) are available through: Most "unblocked" versions found on sites like Google