the validity of the proposal is until Dec 31st,2009 and will be revised upon mutual consent after a period of latest one

问题描述:

the validity of the proposal is until Dec 31st,2009 and will be revised upon mutual consent after a period of latest one year``
这是合同里的"after a period of latest one year"一句话,这怎么翻译呢?

after a period of latest one year,最近的一年时间后