no member named 'max_digits10' in 'Eigen::NumTraitsboost::multiprecision::...

Summary

I am working to update a project from Eigen 3.x to Eigen 5. One of the issues I encountered was a build error noting that for Boost multiprecision types NumTraits does not contain a max_digits10 member. Previously this has never been an issue however it appears as if print_matrix (part of now calls:

explicit_precision = significant_decimals_impl<Scalar>::run();

which maps to:

static inline int run() { return NumTraits<Scalar>::max_digits10(); }

And hence triggers the issue.