In Mandarin, how would you say:
But only X years ago, in month Z of Year Y ...
Now, they say the sun is red. But only two years ago, in September 2015, they said the sun was blue.
Please note that I would like to convey the meaning of "on the contrary (of the situation earlier), now the opposite situation ...". If possible, I am looking to say so as one would say it in Taiwan, not as one would say it in China.
Please answer using traditional characters.