One fo the last changes made by the Royal Spanish Academy last year was just to simplify the use of Solo. This use is very interesting as it gets pretty confusing if you dont put it in context correctly. For instance, if you have a sentence like Juan está solo, is working as an adjetive, Juan is «alone». If we use it as it was used before with a stress: Juan sólo tiene dos entradas para el cine, Juan has only two tickets for the cinema, the function here is «just, only». Now, we will use solo without stress for which we will have to use it correctly in context, not that difficult if you are paying attention.
Hope this helps, simple, but eventually tricky if you are at work trying to write a good email in spanish language for your client.
tilln next time!