1.1 New for Cycle 31

We have made the following updates to the WFC3 Instrument Handbook for this cycle:

• We have updated information, plots, and references throughout the handbook based on the nine Instrument Science Reports (ISRs) released in 2022.
• We have added a plot showing WFC3/UVIS gain stability over time (Figure 5.7) and updated gain values (Table 5.3) in Section 5.4.6.
• We have updated plots of WFC3/UVIS dark current (Figure 5.8 and Figure 5.9) in Section 5.4.8 and WFC3/UVIS hot pixels (Figure 5.13 and 5.14) in Section 5.4.9.
• We have updated Table 6.8 in Section 6.6.2 with WFC3/UVIS 1 empirical encircled energy fractions for select apertures.

• We have added Table 6.9 to Section 6.7.2 to quantify the numbers of science and overscan columns and rows in unbinned and binned UVIS images.

• We have updated the discussion of Charge Transfer Efficiency in Section 6.9, including a new plot (Figure 6.22) that quantifies the charge trailing from hot pixels.

• We have added images to Section 6.10.6 to illustrate Dragon's Breath and the location of stars off the detector that cause it (Figure 6.27) and to illustrate figure-8 ghosts (Figure 6.28).

• We have updated Table 7.6 in Section 7.6.2 with WFC3/IR empirical encircled energy fractions for select apertures.
• We have added a summary of the WFC3 calibration plan for the upcoming cycle in Appendix E  (Section E.16).