There's a swan song coming for you...

A breath of fresh air, a Right Proper shaders mod built from the ground up for Minecraft 1.7.10!
Designed with compatibility-first, around supporting modpacks old and new, tested against era-appropriate shaderpacks.

Compatibility

Compatible with most other popular client-side optimization and graphics mods, including but not limited to:

FalseTweaks
Beddium
Right Proper Lighting Engine
Right Proper MCPatcher
HodgePodge
FastCraft
CoreTweaks
ArchaicFix
BugTorch
NotFine

With expected incompatibilities with:

OptiFine (any)
Original ShadersMod
MCPatcher: Forge (use Right Proper MCPatcher)
Neodymium (use Beddium)
Angelica (May work with certain modules)
OptimizationsAndTweaks (O&T has very aggressive patches that break with most other graphics mods. Do not use it.)

Technical

SwanSong is a standalone replacement for ShadersMod, with initial support focused on shaders that already work with OptiFine 1.7.10_HD_U_E7.

It is not a backport of Iris, nor a direct descendant of ShadersMod or the GLSL Shaders mod. Outside of acting as an implementation of the specification pioneered by said mods.

A few other goodies such as threaded screenshots, OptiFine-like zooming, and a faster font rendering module are included as a bonus!