  One of the major upcoming challenges in particle physics is achieving precise
measurements of the Z, W, and H bosons, as well as the top quark. To meet these
targets, the next e\textsuperscript{+}e\textsuperscript{-} collider complex,
FCC-ee, will need to achieve unprecedented luminosities. The FCC-IS European
Study is investigating the feasibility of these challenges, with a cornerstone
of the study being the design and optimization of the high-energy booster
(HEB). This paper provides an update on the status of the HEB of FCC-ee in
light of recent developments in the injector and collider survey, as well as an
overview of ongoing work on longitudinal stability and design robustness in
relation to field, alignment, and diagnostics errors. Constraints and effects
related to the design frequency of the accelerating cavities, as well as
collective effects, are also highlighted. Lastly, the paper presents an
investigation into an alternative arcs cell design.
