Lines are quoted from the official notes; buff/nerf tags are auto-classified from the numbers and can be wrong. Covers the 14 most recent Dota 2 patches PatchMeter has fetched.
✕removedDistortion FieldNo longer levels with Chronosphere
⇄adjustDistortion FieldNow only applies to projectiles targeting Faceless Void or an allied hero within a 1200 radius of him
▼nerfDistortion FieldEnemy attack projectile speed slow rescaled from 35/40/45/50% to 40%
⇄adjustTime WalkAghanim's Scepter now also provides Reverse Time Walk sub-ability
✕removedTime WalkAghanim's Scepter Time Lock attacks will no longer miss if Reverse Time Walk is used too quickly after Time Walk
✕removedTime WalkNo longer upgraded with Aghanim's Shard
✕removedTime DilationDuration no longer counts down while under effect of Chronosphere
⇄adjustTime DilationNow upgraded with Aghanim's Shard
⇄adjustTime DilationIncreases Attack/Movement Slow per cooldown by 5/5%. Provides Faceless Void with bonus movement and attack speed by the same values per each enemy cooldown extended. The bonus degrades over the duration of the buff
▲buffTime DilationThis buff also doesn't count down under effect of Chronosphere
⇄adjustChronosphereNow the default ultimate ability