[ft] Monochrome rendering changes with 2.8

[chris]

Hello,

I just updated from version 2.6.3 to 2.8.

I am using FT_LOAD_TARGET_MONO to render for example Geneva.ttf in 
monochrome mode at 7 points 96 DPI. As expected the change to v40 made 
the text ugly, so I switched back to v35 by setting the truetype 
interpreter-version property.

1) Is this the correct / recommended / future-proof way to render 
monochrome glyphs or do I need to tweak other settings?

2) In some cases the ascender / descender values changed. 

From 2.6.3:
Loading font GENEVA.TTF     7
 font.fm.textHeight        12
 font.face.size.metrics.ascender         9       576
 font.face.size.metrics.descender        -2      -128

To 2.8:
Loading font GENEVA.TTF     7
 font.fm.textHeight        12
 font.face.size.metrics.ascender        10       640
 font.face.size.metrics.descender        -3      -192

While not a big problem itself it disturbs my layout, so I like to know 
why this happened and  which values are correct before adjusting my 
layout to the new values?

Thanks for any advice!

Chris