noted supported remarkable system versions

Installation-on-ReMarkable.md

@@ -1,6 +1,6 @@
 ## Installation via Toltec
 
-1. Install [Toltec](https://toltec-dev.org/)
+1. Install [Toltec](https://toltec-dev.org/) (currently requires ReMarkable system version between 2.6.1.71 and 2.15.1.1189)
 2. Run: 
 ```
 opkg install koreader
@@ -10,7 +10,7 @@ opkg install koreader
 
 ## Manual installation
 
-0. Install [rm2fb](https://github.com/ddvk/remarkable2-framebuffer#installation) (reMarkable 2)
+0. Install [rm2fb](https://github.com/ddvk/remarkable2-framebuffer#installation) (reMarkable 2 only; currently requires ReMarkable system version 3.3.* or below)
 1. Download the [latest release](https://ota.koreader.rocks/) of KOReader
 2. Copy the file to your device:
 ```