Unable to migrate from Tiny 2313 to tiny 4313 in 1.0.6 and missing both in 1.6.5

I have replaced the 2313 which was getting a little full, in a working project, with a larger 4313 device.
I had already modified my "Boards.txt" to allow me to select a 2313 or, a 4313 and this was working with a 2313 on V1.0.6 a treat.

When I select 4313 in , with a 4313 device on my project, I get a complaint "unknown MCU attiny4313 specified" and a long list of available processors which includes the 2313 but not the 4313.

IF I simply select the 2313 (with a 4313 target chip), I get a verbose list of errors in the form

"In file included from C:\arduino-1.0.6-windows\arduino-1.0.6\hardware\tiny\cores\tiny/wiring_private.h:32,
from C:\arduino-1.0.6-windows\arduino-1.0.6\hardware\tiny\cores\tiny\pins_arduino.c:38:
c:/arduino-1.0.6-windows/arduino-1.0.6/hardware/tools/avr/lib/gcc/../../avr/include/avr/delay.h:36:2: warning: #warning "This file has been moved to <util/delay.h>."
C:\arduino-1.0.6-windows\arduino-1.0.6\hardware\tiny\cores\tiny\pins_arduino.c:70: warning: initialization makes integer from pointer without a cast
C:\arduino-1.0.6-windows\arduino-1.0.6\hardware\tiny\cores\tiny\pins_arduino.c:71: warning: initialization makes integer from pointer without a cast
C:\arduino-1.0.6-windows\arduino-1.0.6\hardware\tiny\cores\tiny\pins_arduino.c:73: warning: initialization makes integer from pointer without a cast" ...

... and this goes on for a while and which I don't get if I plug in a 2313 target board, (2313 selected) so the IDE can tell the chip is the 'wrong one'

I downloaded the latest V1.6.5 and that just does my head in as getting that to program a 2313 or a 4313 seems nigh on impossible.
If you aren't using a recognised board, you are stuffed, which I am sure is NOT the case ?

Simply adding a new folder to the folder, which was all that was required in 1.0.6 doesn't work, so NOW, I have TWO IDE's that won't program the 4313 and the 1.6.5 IDE won't do either 2313/4313.

This may be simple to you guys but not me. I have programmed PIC's for decades. What am I missing ?

SOLVED.
Ditching 1.0.6 as a bad job, I have tweaked V1.6.5 (properly) using arduino-tiny-0150-0020.zip

I needed to create a txt file called "Boards.txt" AND tweak platform.txt in this tiny folder to include the line... "compiler.path={runtime.ide.path}/hardware/tools/avr/bin/"

All of this being guided by a pal on Skype who has been through the misery already who has more patience than I do.

problem resolved.

You could always just use a core that's been properly updated for 1.6.5, like the one in my sig (second link).

It supports almost every tiny, and I've just been testing out the 4313, 2313 chips, and they seem to work well