Q: I recently retired, and plan to spend time at recreational vehicle parks. Most of these parks have free Wi-Fi, but the passwords are often simple, such as 1111. A friend warned me against using these public Wi-Fi hot spots because of security concerns. I could use my cellphone to create my own private Wi-Fi hot spot, but that gets expensive because it uses up my data plan. What can I do?

Bob Hunter, Bloomington

A: Free Wi-Fi hot spots are notoriously unsafe because much of your data can be easily intercepted by hackers, who could snare your personal information and passwords, or put malicious software on your computer. The problem has been lessened by the decision of banks, large retailers and some e-mail systems to encrypt communications with their websites, but much of the internet still doesn't have that protection.

You can avoid the hazards of public Wi-Fi networks by using a virtual private network (VPN.) It will funnel your internet data through an encrypted (coded) connection to the VPN provider's server, where it is then passed on to its destination. Any communication from websites is channeled back through the VPN server to your computer. As a result, any hackers lurking on the public Wi-Fi hot spot are shut out.

Experts say that the safest VPNs are those that incorporate a "kill switch." If the VPN connection fails, the kill switch disconnects your computer from the internet before it can revert to an unprotected connection. Some VPN providers that offer kill-switch capability are PureVPN ($71 a year, tinyurl.com/m2s6s54), IPVanish VPN ($78 a year, tinyurl.com/zpo668c) and Private internet Access ($40 a year, tinyurl.com/3lt9ynx).

There are still concerns about VPNs. Some experts fear that hackers will take advantage of the moments between when you connect to the internet and when your VPN service begins encrypting your data (see tinyurl.com/menjuq9). It's probably a small risk, but it's good to remember that no security software is foolproof.

Q: I'm trying to wirelessly update my iPhone 6 and iPad 4 to Apple's iOS 10.2.1 operating system from their present iOS 9.3.1. But I can only get as far as agreeing to the update; after that I get a message that the update can't install because I'm no longer connected to the internet — even though I'm connected by Wi-Fi. What can I do?

Margaret Millington, Minneapolis

A: Apple's iOS 10.2.1 is no longer available, but you can upgrade to iOS 10.3.1. If the problem persists, remove the update from your phone and iPad and download it again.

To remove the update, go to Settings and tap "general," then tap "storage & iCloud usage." Under the "storage" heading, tap "manage storage." In the resulting list of apps, find the iOS update, tap it, then tap "delete update."

To download the update again, go to "Settings" and tap "general," then tap "software update." In the resulting menu, tap "download and install."

If that doesn't work, you will need to install the update by connecting your devices to iTunes on a computer See tinyurl.com/nnojxm7 and scroll down to "update your device using iTunes."

E-mail tech questions to steve.j.alexander@gmail.com. Include name, city and telephone number.