This is just a short post to remind everyone that the End-of-Marketing date for z13 or z13s upgrades is just a month away. Upgrades that involve real hardware (such as additional channels or zEDC cards or coupling adapters) must be ordered by June 30, 2019. LIC-only upgrades can be ordered up until June 30, 2020 (refer to IBM US announcement letter 918-110 for the details).
This is especially important for anyone that has one or more z13s CPCs with InfiniBand Coupling Links. The IBM ZR1 announcement (118-018) states that the ZR1 and future Z CPCs will not support InfiniBand Coupling Links (the enterprise-class z14, on the other hand, supports both InfiniBand and the newer Coupling Links, which is why this is more of an issue for z13s than z13 customers). So, if you have a z13s today that is connected to other CPCs using InfiniBand Coupling Links, you need to think about how you will replace that CPC. If the CPCs that it is connected to also only have InfiniBand Coupling Links, the ZR1 or its future replacement will not be able to connect to those other CPCs. The only way to ensure full connectivity is to order ICA-SR (Short Range) or CE-LR (Long Range) Coupling Links for your InfiniBand-only z13 or z13s CPCs before the end of June. There is no point thinking about this when you decide to move to a ZR1 6 months from now, and you can no longer get the newer links for your z13 or z13s.
An excellent source of information about End of Marketing and End of Service dates for Z CPCs is the IBM Techdoc TD105503, IBM Mainframe Life Cycle History, maintained by Don Clarke. Another excellent source of information about connecting anything to a Z CPC is the IBM Redbook, IBM Z Connectivity Handbook, SG24-5444.