Samsung Galaxy Note 3
Samsung Galaxy Note 3Screenshot/Samsung official

Arch-rivals Samsung and Apple have not revealed the release date of their respective upcoming flagship devices, Galaxy Note 4 and iPhone 6, but several reports have suggested that the two much-awaited smartphones would be launched at around the same time.

Samsung Galaxy Note 4 and iPhone 6 will most probably be released in the month of September though there are reports of Apple's plan to unveil its smartphone in August.

A reliable insider has claimed that Galaxy Note 4 would be unveiled on 3 September this year and the invitation to the Unpacked event would be sent out in mid-August, according to Android Geeks.

The Korea Times had earlier reported citing sources that the device would be unveiled at the the upcoming annual IFA trade fair in Berlin, Germany this September.

On the other hand, the Cupertino giant is expected to unveil its flagship smartphone about two weeks after Galaxy Note 4 is announced. The leaked internal documents of German wireless carrier Deutsche Telekom have revealed that iPhone 6 would be unveiled on 19 September, according to a report by German website ApfelPage

A research note by UBS Managing Director Steve Milunovich (via Barron's) had earlier claimed that 4.7-inch variant of iPhone 6 would be launched either in August or September, which was complimented by Nikkei. There are also reports that the 4.7-inch model would arrive in September, while the larger, 5.5-inch variant would be pushed to next year. However, Reuters recently claimed citing Taiwan's Economic Daily News that the smaller model would be released in August, while the larger one would arrive in September. 

Samsung Galaxy Note 4's real threat will be the 5.5-inch variant of iPhone 6, as the screen size of the devices doesn't differ much. It can have a free run in the smartphone market at least for a few months, if the larger variant of iPhone 6 is pushed to next year, but otherwise it will have to fight out in the market.

The South Korean electronics giant's upcoming device from Note series is likely to sport a 5.7 inch super Amoled display with a resolution of 2560 x 1440 giving a ppi of 500+, powered by Quad Core Snapdragon 805 processor that clock at 2.5GHz, packed with 3GB LPDDR3 RAM and have a flexible display.

Samsung4Note website reported that the device would have a 16MP rear camera with ISOCELL technology, 4K video recording and a 2MP front camera with 1080p video recording and S-Pen stylus with updated gestures and air command.

On the other hand, Apple Inc. is expected to launch two variants of iPhone 6, one with a 4.7-inch display and the other one with a 5.5-inch, both with full scratch-free sapphire crystal glass screen. The devices may have 20-nanometer A8 chip (64-bit) processor under the hood, run on either iOS 8 or iOS 7.2 and feature 8MP camera with upgrades like flash and Optical Image Stabilisation.

The 4.7-inch model may have a 1920 x 1080p (440ppi) resolution while the bigger, 5.5-inch variant may have a 2272 × 1280 (510ppi) resolution, according to the South Korean brokerage KDB Daewoo Securities.

A report by Apple Insider, which cited analyst Ming-Chi Kuo, claimed that the devices would feature low temperature polysilicon in-cell touch panels, Touch ID fingerprint security, NFC and metal casing.

Chinese analyst Sun Chang Xu also had claimed that the device might have sensors that can detect pressure, temperature and humidity.