A Stylistic Lineage Tree

Here (opens in a new tab) is Kai Chi Leung's commemoration, which includes the connection to his Chen lineage via Du Yuze.

There seems to be some conflicting information about Du Yuze's teacher Chen Mingbiao and what style he taught. Here is an article about Du, and here a commemoration. From that, it seems to suggest that he learned an old frame and a new frame system.

Chen YanXi would have been the source of the old frame.

And Chen MingBiao the source of the new frame, which seems to have been a blend of small frame with some Zhaobao thunder (Hulei) flavor. The small frame was the original 'new frame' and Cheng MingBiao's was a little more unique. But both are different from Chen Fake's 'new frame', which most people mean when they say 'new frame' today.

Here (opens in a new tab) is a video of Du Yuze performing Chen YiLu (First Path). This would appear to be his transmission of Chen YanXi's old frame.

Here (opens in a new tab) is that same form, where again it is listed as the old frame. In the comments someone says it is a modified version of Chen Xin's XiaoJia, Small Frame. However, that seems unlikely.

Perhaps this is due to how the old frame generally seems to have many different presentations. And how it can perhaps be seen that Du Yu Ze is utilizing small frame coiling power within the old frame.

Here (opens in a new tab) is that same video, on youtube, titled:
杜毓澤陳氏太極拳老架

Du Yuze, Chen Style Tai Chi Old Frame

For comparison, here (opens in a new tab) is Wang Chang Jiang performing the old frame form. His grandfather Wang Yan was apparently (opens in a new tab) taught together by Chen YanXi and Chen Fake, and ensured the teaching of Chen YanXi's transmission after Chen Fake left for Beijing.

This old frame form bears remarkable similarity to Du Yu Ze's old frame form, revealing the link to Chen YanXi.

This (opens in a new tab) page discussing the overall flavorful history of Taji lineages may also be helpful.