Hi,
V1R5is the latest software version available. I'm afraid the link is stored on Carrier support website.
http://support.huawei.com/carrier/navi?coltype=software#col=software&detailId=PBI1-3283016&path=PBI1-7275726/PBI1-7275754/PBI1-7275849/PBI1-22896245/PBI1-15873
The version is controlled and you may need to fill in the application and to get approval from service representative.
Note:
CX200D is EoS from 2017, see below link:
http://www.huawei.com/en/products-lifecycle