PM11 at the Hallsta paper mill is undergoing an upgrade to meet more stringent requirements for smoothness and glossiness. At the beginning of May, the machine was at a standstill for six days for upgrading and replacement of components.Hallsta mill is located in Hallstavik north of Stockholm. The three paper machines at the mill produces MF magazine paper and a range of special qualities of wood-containing printing paper. The production amounts to aproximately 700,000 tons.