IDE 1.6.3 is now available for download

Hi everyone

we've just released Arduino IDE version 1.6.3. It includes lots of fixes reported here on the forum, on github issues and on the developers mailing list.

It also contains two new big features: an integrated one-click way to install additional libraries and support additional boards. 144 libraries are already in the list. If you want to add your preferred library to the list, please open an issue on github.

Here is a brief list of the fixes

  • Libraries and Boards Managers, for installing additional libraries and boards support in one click
  • Smaller download size: the IDE bundles only the AVR support now, SAM support (for Arduino Due and ARM mcus) is available through Boards Manager
  • Added new Arduino Language color highlight
  • Advise of duplicate libraries after compiling. Thanks @PaulStoffregen
  • Super fast tools menu, especially on Windows
  • Updated libraries

Also featured on the Arduino Blog

The complete list of changes is available here.

Any feedback is very much appreciated.



I hope we can still change the compiler optimisations.

Yes you can. Just keep in mind that by upgrading/downgrading/removing (for example) the avr core, you have to reapply your changes. Not likely to happen every week, but still something to keep in mind

I hope we can still change the compiler optimisations.

I read your instructable page, but didn't see the code you used for measuring the performance. Is it published somewhere?

I'd like to give it a try here on a couple difference boards with other settings.

Hi Paul, as we are going off topic I will keep this brief.

I used a variant of the UTFT library "UTFT_Demo_320x240" driving an ILI9341 SPI TFT, all delay() lines commented out and the performance skewing 10,000 pixel test at the end cut down to 1000 pixels. See Step 2 here.
Performance shown in Step 2 here.

I would run it via the UTFT library as it may be a pain to get it to run on a Teensy under my AVR optimised GFX library.
I thought about running a performance test suite that used mixes of tight loops and floating point stuff etc but I just want to get my code running fast :-), even a delay free Blink runs 15% faster with the -O2 option (need a 'scope to see that!)

Oops that was not short!

After installing the new version all my libraries were deleted! Awesome… :sob:

Siod, I don’t really think so. It’s likely you used a custom sketchbook location. Your libraries are still there, untouched

No, believe me. I installed it to the same Arduino directory where the older version was located, so it should just overwrite the old version. But now all my installed libraries are gone, have to reínstall all of them...

I believe you, but we are talking about two different things. I'll rephrase: where is your sketchbook located? On windows, by default, it's in c:\users\your_username\Documents\Arduino

Federico, there are some corner cases where things go very wrong. Here's one I confirmed weeks ago, after many messages back and forth with a forum user:

With virtually no info given, other than "all my libraries were deleted", of course it's impossible to know if it was this or something else, or simply a mistake, or if they libraries are really still on that computer somewhere. But my point is there are indeed some unexpected cases like issue 2719, which normally don't happen, but can occur if users misconfigure settings, where the Arduino IDE does very wrong things.

Ack, thanks Paul. I'll give that issue a priority boost

I tested the 1.6.3 and went back to 1.6.1

I use NANO, MEGA and DUE.

My install location was

sketches in

additional libraries in

I modified for me in 1.6.1 and in every former version :wink:
print.h, print.cpp in hardware avr and sam (some additional new print(f)_P and temperature prints with onewire-sensors etc.)
wiring_digital.cpp in sam (fixing the bug not able to reread outputs back with DUE)
EthernetClient.h and EthernetClient.cpp adding

uint8_t *EthernetClient::getRemoteIP(uint8_t remoteIP[]) //adds remote ip address
	W5100.readSnDIPR(_sock, remoteIP);
	return remoteIP;

Up to 1.6.1 all is in one directory so I can ZIP the whole thing and put at on an USB-Stick, to the laptop and making a backup.

Since 1.6.2 the additional SAM support goes not to install dir but somewhere in the user directory(additional 600 Megs).

This is the reason I went back to 1.6.1, because grabbing through sources in different partitions/directories when strange things happen or for a look in some arduino functions with 1.6.2/1.6.3 is a no go for me.

Uninstalling 1.6.3 will delete the whole install directory
d:\programs\arduino_1.6.3 inclusive modified files, sketches and libraries

Why ever would you try to set things up this way?

My install location was

sketches in

This isn't exactly issue #2719, but it's a configuration the IDE should detect and at least warn with a strongly worded message, or perhaps refuse to run.

Today, the Arduino IDE does not check if you've followed certain assumptions built into the IDE's design, mainly that the sketchbook folder and the IDE install location and the preferences+packages folders never overlap. Placing them in the same location, or one within any of the others is an invalid installation.

Hopefully we'll manage to add checks for this into 1.6.4. I might write the code, if Federico & the official Arduino devs don't get to it first. We just can't keep allowing the IDE to run without any warning of these wrong installations.

Help! I am using Due and there seems to be only AVR support 1.6.3! :frowning:

When you click Tools > Board to try selecting Due, notice the very first item: "Boards Manager..."

That new feature lets you add Due.


is it possible to add the watchdog-functions for the DUE in the new release as posted in Add Due watchdog functions; modified according to feedback supplied · bobc/Arduino@87a9a1f · GitHub ?

Thanks a lot


Thanks. It does indeed seem to add the Due support but there is no sign of the SAM Cortex stuff in C:\Program Files (x86)\Arduino\hardware\arduino or the GNU ARM compiler in C:\Program Files (x86)\Arduino\hardware\tools. It seems to compile sketches but then will not download to the Due.

It looks like it is still using the Avr tools etc. and is very confused. The previous 1.6.0 I was using was fine!

Today, the Arduino IDE does not check if you’ve followed certain assumptions built into the IDE’s design, mainly that the sketchbook folder and the IDE install location and the preferences+packages folders never overlap. Placing them in the same location, or one within any of the others is an invalid installation.

The problem reported in earlier versions of not being able to burn a bootloader onto Atemga8 (Arduino NG) continues. Bit annoying as I like to have students make breadboard Arduinos, so can learn a bit about what makes up the board and make small senors boards for projects. Right now we have to use 1.0.6
Otherwise no problems so far

Very true, Paul, however the locations for AVR files and Due files have nothing in common. The hardware folder for AVR devices is in the Arduino installation folder. Boards Manager installs Due files deep inside the Users directory on a Win7 system.