Both are correct from the book I read recently. If we mark every tone by numbers, there will be : High tone:1.2.3.7 Low tone:4.5.6.9 Mid Tone :8 No tone 7,tone 8 and tone 9 in around 50% of Cantonese. That means half Cantonese only have 6 tones, the other half have 9 tones.

事实上粤语（广东话）有九声六调，但是很多广东人都搞不清楚那些tones. You can visit this website: http://en.wikipedia.org/wiki/Guangdong_Romanization#Cantonese

jyutping