We would like to see photos of the spots on the leaves so we can see what you may be dealing with.  In general this tree can be subject to leaf spots and twig blights but neither are serious. Send photos of the whole tree, around the base, and affected foliage.
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Right now it's mostly affecting the lower branches.  Last year it covered the tree.  It may not kill it, but it makes it look pretty miserable.

This looks like a fungal leaf spot. This doesn't look terrible to us. This late in the year your best option is sanitation, which consists of cleaning up the leaves when they fall and getting them out of the yard to reduce the pathogen load in the environment for next season.  It looks like only a small proportion of the tree is affected this year.  You could (on a dry day) pick off these leaves and dispose of them if you are so inclined.
Each year disease pressure is based on how wet the season is, so as you've seen, some years are worse than others.   We don't generally recommend fungicide sprays for ornamental trees, especially when the disease is not serious, but you could use a fungicide in the spring just after the leaves are fully expanded, and then repeat it 2 weeks later.
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