On the Product Information Bulletin for Datacom/Server Service Update 15.0 S1902, you can read:
This Service Update delivers additional capabilities including all maintenance updates through January 2019
Being so, you need to download all the Datacom/Server PTFs published after January 2019.
- Sign in to https://support.broadcom.com/
- Click on My Downloads link
- In Search By Product Name type datacom
- Click on DATACOM
- Click on Solutions tab
- Click on Datacom Server MVS and click on 15.0
- This will show all current PTFs
- Select Z/OS as OS
- Select DATACOM SERVER as Component
- Type 02/01/2019 as start date
- You should see 28 PTFs
- Click Add All To Download Manager button
- Click Download All button
- As you have all the solutions before 02/01/2019, as you installed S1901, uncheck the "Do you want a complete package for all?" button
- Click the Start Download button
- Choose your preferred method to download the PTFs package