Question: I've developed a project and set its deployment target 10.3. I then gave project to client who have iphone 7 plus and ios 10.3. This is working on his device. I gave the same product to another friend who have iphone 5 and ios version lower than 10. App is not running on iPhone 5. That device is saying that the app has minimum deployment target 10.3. I'm very much confused about deployment target. How could I manage those things for all devices and ios versions? Please anyone help me.

Answer: 
You forgot the multiplier (see argument `ci` in `?plot.specaccum`). What you drew were for a ~68% confidence interval. Multiplying by 2 (`ci = 2`) gives an approximate 95% confidence interval, which is what `plot.specaccum` draws by default.

Including the (default) multiplier in a modification of the code you used

```
plot(result)
with(result, arrows(sites, richness - (2 * sd), sites, richness + (2 * sd),
                    angle = 90, code = 3, length = 0.05))

```

we get:

[![enter image description here](https://i.stack.imgur.com/afdDZ.png)](https://i.stack.imgur.com/afdDZ.png)

You can ignore the warning; the standard error of the last data point drawn is zero

```
> result$sd
 [1] 2.3510636 1.8763851 1.5722711 1.4469584 1.3901594 1.3530349 1.3164796
 [8] 1.2749034 1.2282010 1.1763410 1.1193437 1.0564537 0.9874094 0.9115998
[15] 0.8286890 0.7380921 0.6333903 0.5139710 0.3570714 0.0000000

```

and `arrow()` is just warning you that it won't draw a length 0 arrow.
The **vegan** repository in [github](https://github.com/vegandevs/vegan/) has now an option for drawing those short horizontal bars to the error bars with argument `ci.length`. The default is zero (no horizontal bars) to preserve the old behaviour.