Determining the Technology Refresh PTF level installed

If you are on V7R1.

From IBM Redbook:
IBM i 7.1 Technical Overview with Technology Refresh Updates
December 2014

Determining the Technology Refresh PTF level installed
To determine the Technology Refresh PTF level of 5770-999, use the Display PTF Status
(DSPPTF) command for product 5770-999, as shown in Figure 1-4.
Technology Refresh PTFs for this product are in the format of MF99nnn. The highest number
Technology Refresh PTF on your system, matched with Table 1-1 on page 7, indicates the
Technology Refresh level for this product.

Also known as technical release or TR level.