Hi @AnnaPapiernik , indeed it seems like ‘Highlight critical path’ is a Business+ feature, which also applies for the Timeline view too.
@Bastien_Siebman , you may want to include this in Differences between features overlapping in tiers (you may also want to shift all the tasks to the right a bit too 
)
Conclusion: Timeline and Gantt views are available in Premium but without ‘Highlight critical path’ feature.