Two very different things have happened at Forest Gate which I find very odd.
Platforms 3 and 4 have had their station name signs replaced with white text on a plain blue background (no roundels) with the text in all upper case (pretty sure it's Johnston but strangely hard to tell when in all upper case).
Platform 1 on the other hand have had purple roundels added to match those seen on the unopened core section.
Why the inconsistency? The purple roundels you assume were going to happen anyway but why replace the existing blue TfL Rail signs on platforms 3 and 4? I assume they're to be replaced again soon anyway with purple roundels.
Could it just be that the signs on all bar platform 1 are temporary fixtures as works are yet to be completed?
Here’s a comparison of the two fonts side by side.
Absolutely but they already had temporary signs, they had full width stickers over the old signs which was similar but was in sentence case and featured the TfL Rail logo (still on platform 2) so I don't understand the need to replace them for temporary signs again.
From that I can confidently say it's definitely the Johnston font, it's what you see on the bottom row.